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+https://freecodecamp.org/[image:https://cdn.freecodecamp.org/testable-projects-fcc/images/fcc_secondary.svg[freeCodeCamp]]
+
+**Learn Foundational Math 1 by Building an Equation Solver** Each of
+these steps will lead you toward the Certification Project. First you
+have to copy the files and set them up in your Google Drive.
+
+== ↓ *Do this first* ↓
+
+Make sure you are logged into your Google account, and copy this
+notebook to your own account. Click ``File'' (at the top of this page)
+and then click ``Save a copy in Drive.'' The file will be in a folder
+called ``Colab Notebooks'' in your Google Drive.
+
+#Directions - Click to expand the next step Click on the little triangle
+next to the word ``Step'' to do that step. Once you complete a step,
+click the triangle to expand the next step.
+
+== Step 0 - Acquire the testing library
+
+Please run this code to get the library file from FreeCodeCamp. Each
+step will use this library to test your code. You do not need to edit
+anything; just run this code cell and wait a few seconds until it tells
+you to go on to the next step.
+
+
++*In[1]:*+
+[source, ipython3]
+----
+# You may need to run this cell at the beginning of each new session
+
+!pip install requests
+
+# This will just take a few seconds
+
+import requests
+
+# Get the library from GitHub
+url = 'https://raw.githubusercontent.com/freeCodeCamp/cdn/main/build/math-cert-tests/math-code-test-a.py'
+r = requests.get(url)
+
+# Save the library in a local working directory
+with open('math_code_test_a.py', 'w') as f:
+    f.write(r.text)
+
+# Now you can import the library
+import math_code_test_a as test
+
+# This will tell you if the code works
+test.step19()
+----
+
+
++*Out[1]:*+
+----
+Requirement already satisfied: requests in /usr/local/lib/python3.8/dist-packages (2.28.2)
+Requirement already satisfied: certifi>=2017.4.17 in /usr/lib/python3/dist-packages (from requests) (2019.11.28)
+Requirement already satisfied: idna<4,>=2.5 in /usr/lib/python3/dist-packages (from requests) (2.8)
+Requirement already satisfied: charset-normalizer<4,>=2 in /usr/local/lib/python3.8/dist-packages (from requests) (3.1.0)
+Requirement already satisfied: urllib3<1.27,>=1.21.1 in /usr/lib/python3/dist-packages (from requests) (1.25.8)
+WARNING: Running pip as the 'root' user can result in broken permissions and conflicting behaviour with the system package manager. It is recommended to use a virtual environment instead: https://pip.pypa.io/warnings/venv
+
+[notice] A new release of pip is available: 23.0.1 -> 23.1.2
+[notice] To update, run: python3 -m pip install --upgrade pip
+
+ Test passed. You can go on to the next step.
+----
+
+== Step 1 - Add
+
+To help you get familiar with Colab notebooks, you will start with the
+basics. Python uses `+`, `-`, `*`, and `/` for the four math operations:
+add, subtract, multiply, and divide. When you add two numbers, the
+result is the sum. Use addition within the `print` statement to get the
+sum of `a` and `b`. To run the code, you can hit ``shift'' and ``enter''
+or you can click the run button (the triangle inside a circle).
+
+
++*In[2]:*+
+[source, ipython3]
+----
+a=1
+b=2
+
+# Change the next line to print the sum of a and b
+print(a+b)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step01(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[2]:*+
+----
+3
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 2 - Subtract
+
+When you subtract two numbers, the result is the difference. Use
+subtraction in the print statement to get the difference between `c` and
+`d`. Remember to use ``shift'' and ``enter'' to run the code.
+
+
++*In[3]:*+
+[source, ipython3]
+----
+c = 7
+d = 3
+
+# Change the next line to print the positive difference between c and d
+print(c-d)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step02(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[3]:*+
+----
+4
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 3 - Multiply
+
+When you multiply numbers, the result is the product. Use multiplication
+within the print statement to get the product of `e` and `f`:
+
+
++*In[4]:*+
+[source, ipython3]
+----
+e = 2
+f = 4
+
+# Change the next line to print the product of e and f
+print(e*f)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step03(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[4]:*+
+----
+8
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 4 - Divide
+
+When you divide two numbers, the result is the quotient. Use division
+within the print statement to get the quotient of `g` and `h`:
+
+
++*In[5]:*+
+[source, ipython3]
+----
+g = 8
+h = 4
+
+# Change the next line
+print(g/h)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step04(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[5]:*+
+----
+2.0
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 5 - Cast Input
+
+User input comes in as a string, so you need to cast it as an integer or
+a float before doing any math. The code below asks for input and uses
+`int()` to cast it as an integer. Follow the model and cast the second
+variable as an integer. Then run the code an test it. (Remember to hit
+``enter'' after you type each integer in the box.)
+
+
++*In[6]:*+
+[source, ipython3]
+----
+strA = input('Enter a positive integer: ')
+intA = int(strA)
+
+strB = input('Enter another positive integer: ')
+
+# Change the next line but keep the variable name:
+intB = int(strB)
+
+
+print(intA+intB)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step05(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[6]:*+
+----
+Enter a positive integer:  23
+Enter another positive integer:  53
+
+76
+ 
+Code test passed
+Go on to the next step
+----
+
+#Step 6 - Input and cast on the same line
+
+You can prompt for input and cast that input on the same line. Notice
+the nested functions in the first line of code. Follow that model to
+prompt for input and cast that input as an integer on the same line.
+
+
++*In[7]:*+
+[source, ipython3]
+----
+intA = int(input('Enter an integer: '))
+
+# Change the next line but keep the variable name:
+intB = int(input('Enter an integer: '))
+
+
+print(intA+intB)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step06(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[7]:*+
+----
+Enter an integer:  234
+Enter an integer:  2342
+
+2576
+ 
+Code test passed
+Go on to the next step
+----
+
+#Step 7 - Float numbers
+
+A float number allows decimal places. When prompting for a number as
+input, casting that as a float is usually the best choice. Follow the
+model below to prompt for input and cast that input as a float on the
+same line.
+
+
++*In[8]:*+
+[source, ipython3]
+----
+a = float(input('Enter a number: '))
+
+# Change the next line but keep the variable name:
+b = float(input('Enter a number: '))
+
+
+print(a/b)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step07(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[8]:*+
+----
+Enter a number:  3431231
+Enter a number:  341413
+
+10.050088895267608
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 8 - Order of Operations
+
+You may have heard of the order of operations and the acronym PEMDAS,
+which reminds you of the correct order. This means that you do what is
+in Parentheses first, then simplify Exponents. You then do all of the
+Multiplication and Division together, as long as you work from left to
+right and simplify them in order. The same is true of Addition and
+Subtraction: work from left to right and simplify the one the comes up
+next. Python knows the order of operations. In the following code,
+Python will calculate the actual_answer correctly. Notice the use of
+`**` to indicate an exponent. Do the arithmetic in your head (no writing
+code) and change the `your_answer` variable, then run the code to see if
+your_answer matches the actual_answer.
+
+
++*In[9]:*+
+[source, ipython3]
+----
+actual_answer = (1+4*2-14/2)**3
+
+# Put your answer on the following line:
+your_answer = 8
+
+print('Actual answer is ', actual_answer)
+print('Your answer is ', your_answer)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step08(your_answer)
+----
+
+
++*Out[9]:*+
+----
+Actual answer is  8.0
+Your answer is  8
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 9 - Remainder and Modulus
+
+A remainder is what is left over when you try to divide two numbers and
+it doesn’t divide evenly. The remainder of 10 / 4 is 2 because 4 goes
+into 10 two whole times, with 2 left over. The modulus (`%`) operator
+will output the remainder, so `10 % 4` will return 2. Use the modulus
+operator to find the remainder of a divided by b:
+
+
++*In[10]:*+
+[source, ipython3]
+----
+a = 14
+b = 6
+
+# Change this line
+print(a%b)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step09(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[10]:*+
+----
+2
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 10 - Modulus and Factors
+
+Use an `if` statement with the modulus operator to find out if one
+number is a factor of another. For example, to see if 5 is a factor of
+20, you can test `if 20 % 5 == 0`. If there’s no remainder, the second
+number is a factor of the first. Remember that Python comparisons use
+`==` to test values. Remember that the `if` statement ends in a colon
+(`:`) and the resulting block is indented four spaces. Finish the code
+below to print ``true'' if `test_factor` is a factor of `number` and
+print ``false'' if it is not.
+
+
++*In[11]:*+
+[source, ipython3]
+----
+number = int(input('Enter an integer: '))
+test_factor = int(input('Enter an integer to see if it’s a factor: '))
+
+# Change the next line to test the factor:
+if number % test_factor == 0:
+    print('true')
+else:
+    print('false')
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step10(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[11]:*+
+----
+Enter an integer:  23423
+Enter an integer to see if it’s a factor:  234242
+
+false
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 11 - Finding Factors
+
+Now you will find all of the factors of a number. This code has a loop
+with a variable, `test_factor`, that iterates through a defined range.
+Remember that the first line defining the loop ends in a colon (:) and
+each line in the loop requires a four-space indent. Change the `if`
+statement to find all the factors of `number`.
+
+
++*In[12]:*+
+[source, ipython3]
+----
+number = int(input('Enter an integer: '))
+
+# Only change the if statement:
+for test_factor in range(1, number+1):
+    if number % test_factor == 0:
+        print(test_factor)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step11(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[12]:*+
+----
+Enter an integer:  441
+
+1
+3
+7
+9
+21
+49
+63
+147
+441
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 12 - Prime Numbers
+
+A prime number is a number whose only factors are 1 and itself. The
+number 5 is prime because its only factors are 1 and 5, but the 6 is not
+prime because it has 1, 2, 3, and 6 as factors. Any number that is not a
+prime is a composite. For each iteration in the loop, `test_number` will
+be a possible factor. Change the `if` statement so that the code prints
+``composite'' if `number` is not prime.
+
+
++*In[13]:*+
+[source, ipython3]
+----
+number = int(input("Enter a positive integer: "))
+
+prime_or_comp = "prime"
+
+for test_number in range(2,number):
+    # Change the if statement to test one factor here:
+    if number % test_number == 0:
+        prime_or_comp = "composite"
+        break
+
+print(prime_or_comp)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step12(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[13]:*+
+----
+Enter a positive integer:  5345
+
+composite
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 13 - Reciprocals
+
+A _reciprocal_ is a number ``flipped.'' The reciprocal of
+latexmath:[$\frac{2}{3}$] is latexmath:[$\frac{3}{2}$] and the
+reciprocal of 5 is latexmath:[$\frac{1}{5}$] because whole numbers have
+denominators of 1. You can multiply a number by its reciprocal to get 1,
+so 5 * latexmath:[$\frac{1}{5}$] = 1 and latexmath:[$\frac{2}{3}$] *
+latexmath:[$\frac{3}{2}$] = 1. To get the reciprocal of a number, take 1
+divided by that number. Trying to get the reciprocal of zero will lead
+to a ``divide by zero'' error. Use a print statement to output the
+reciprocal of `n` as a decimal.
+
+
++*In[14]:*+
+[source, ipython3]
+----
+n = float(input('Enter a number: '))
+
+# Write your code here
+print(1/n)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step13(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[14]:*+
+----
+Enter a number:  535
+
+0.001869158878504673
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 14 - Splitting input
+
+The code below asks for two integers, separated by a comma, then splits
+the input at the comma. Notice the input remains a string, then the
+`split()` function creates an array with two elements. Finish the
+following code to cast the two variables `a` and `b` as `float` numbers,
+then divide the two numbers and print the result.
+
+
++*In[15]:*+
+[source, ipython3]
+----
+nums = input('Enter two numbers, separated by a comma: ')
+sp = nums.split(",")
+
+# Use the next line as a model:
+a = float(sp[0])
+
+# Change the next line to cast the number as a float:
+b = float(sp[1])
+
+# Change the print statement:
+print(a/b)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step14(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[15]:*+
+----
+Enter two numbers, separated by a comma:  324, 543
+
+0.5966850828729282
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 15 - Square Numbers
+
+One factor multiplied by itself will produce a square number, so a
+number raised to an exponent of 2 is that number squared (like
+calculating the area of a square). Python uses `**` to indicate
+exponents. Complete the code to print the square of the input.
+
+
++*In[16]:*+
+[source, ipython3]
+----
+n = float(input('Enter a number to square: '))
+
+# Change this line of code:
+print(n**2)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step15(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[16]:*+
+----
+Enter a number to square:  4
+
+16.0
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 16 - Square Root Function
+
+You can find the square root of a number with the `sqrt()` function. To
+use this function, you need to import the math library. This library
+enables you to use many functions, as you will see in later steps. To
+get the square root of x, you would write `math.sqrt(x)`. Complete the
+code to print the square root of a number.
+
+
++*In[17]:*+
+[source, ipython3]
+----
+import math
+
+n = float(input('Enter a number to find the square root: '))
+
+# Change the next line of code:
+print(math.sqrt(n))
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step16(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[17]:*+
+----
+Enter a number to find the square root:  25
+
+5.0
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 17 - Floor Function
+
+The`floor()` function drops any decimals and sometimes is called the
+integer part of a number. Complete the code to print the floor of a
+number. Notice you `import math` and use `math.floor(n)`
+
+
++*In[18]:*+
+[source, ipython3]
+----
+import math
+
+n = float(input('Enter a number with decimal places: '))
+
+# Change the next line of code:
+print(math.floor(n))
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step17(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[18]:*+
+----
+Enter a number with decimal places:  3.5536363
+
+3
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 18 - Finding Square Factors
+
+This step will combine a few things you have already done. Remember that
+a square number is an integer that is the result of multiplying another
+integer by itself. Just as you created a loop to find factors of an
+integer, here you will find the greatest factor that is a perfect
+square. For example, 2 is a factor of 16, but 2 is not a square number,
+while 4 is a factor and it is a square number, but it is not the
+greatest square factor. The greatest square factor of 16 is 16. The
+greatest square factor of 32 is 16. Complete `if` statement in the loop
+to find the greatest square factor of a number.
+
+
++*In[20]:*+
+[source, ipython3]
+----
+import math
+
+n = int(input('Enter an integer to find the greatest square factor: '))
+
+max_factor = 1
+upper_limit = math.floor(math.sqrt(n)) + 1
+
+# Change one line in this loop:
+for maybe_factor in range(1,upper_limit):
+    if n % (maybe_factor**2) == 0:
+        max_factor = maybe_factor
+
+# Keep this print statement:
+print(max_factor**2)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step18(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[20]:*+
+----
+Enter an integer to find the greatest square factor:  32
+
+16
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 19 - Dividing out Factors
+
+Building upon your code from the previous step, this code will divide
+out the greatest square factor of a number. You don’t need to change
+anything; just run the code below a few times, inputting different
+numbers each time.
+
+
++*In[21]:*+
+[source, ipython3]
+----
+import math
+
+n = int(input('Enter an integer to factor: '))
+upper_limit = math.floor(math.sqrt(n)) + 1
+square_root = 1
+max_factor = 1
+other_factor = 1
+
+# Notice what the loop is doing here
+for maybe_factor in range(1, upper_limit):
+    # Check for square factors
+    if n % (maybe_factor**2) == 0:
+        # Find the greatest square factor
+        max_factor = maybe_factor**2
+
+# Divide out the greatest square factor
+other_factor = n/max_factor
+
+# Display the results
+print("", n, " = ", max_factor, " * ", other_factor)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step19()
+----
+
+
++*Out[21]:*+
+----
+Enter an integer to factor:  56
+
+ 56  =  4  *  14.0
+
+ Test passed. You can go on to the next step.
+----
+
+== Step 20 - Factoring Square Roots
+
+The last four steps prepared you for this. To factor a square root, you
+want to divide out any perfect square factors. For example:
+latexmath:[$\sqrt{12}$] = latexmath:[$\sqrt{4 * 3}$] =
+2latexmath:[$\sqrt{3}$] Because 4 is a square number, the square root of
+4 is now outside the radical. You will import `sympy` and `symbols` to
+use the radical (latexmath:[$\sqrt{x}$]) in the output. Use the code
+from the previous step (without changing much). Your goal is to ask for
+a number and output the factored square root. The radical formatting
+(using sympy and symbols) is already done for you.
+
+
++*In[22]:*+
+[source, ipython3]
+----
+import math
+import sympy
+from sympy import symbols
+
+n = int(input('Without the radical, enter a square root to factor: '))
+
+# Use these variables
+upper_limit = math.floor(math.sqrt(n)) + 1
+max_factor = 1
+other_factor = 1
+square_root = 1
+
+# Notice what the loop is doing here
+for maybe_factor in range(1, upper_limit):
+    if n % (maybe_factor**2) == 0:
+        max_factor = maybe_factor**2
+
+# Divide out the greatest square factor
+other_factor = n/max_factor
+
+# Output - keep this:
+square_root = int(math.sqrt(max_factor))
+other_factor = int(other_factor)
+output = square_root*sympy.sqrt(other_factor)
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step20()
+output
+----
+
+
++*Out[22]:*+
+----
+Without the radical, enter a square root to factor:  32
+
+
+ Test passed. This is this your factored square root:
+
+4*sqrt(2)----
+
+== Step 21 - Rounding
+
+If you only want a certain number of decimal places, use the `round()`
+function. This takes two arguments: the number to round and the number
+of decimal places, so `round(2.468, 2)` will return `2.47`. To round a
+large number instead of a decimal number, make the second argument
+negative, so `round(2345, -3)` will return `2000`. Finish the code below
+so that it prints the first number rounded to the nearest million (six
+zeros) and the second number rounded to 3 decimal places.
+
+
++*In[23]:*+
+[source, ipython3]
+----
+a = 14588132
+b = 0.006538298336
+
+# Write your code here
+print(round(a, -6))
+print(round(b, 3))
+
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step21(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[23]:*+
+----
+15000000
+0.007
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 22 - Fractions, Decimals, Percents
+
+To convert a decimal number to a fraction, let latexmath:[$x$] = the
+number of decimal places. The basic fraction is the number (without the
+decimal point) over 10latexmath:[$^{x}$]. Example: 0.2 =
+latexmath:[$\frac{2}{10}$] and 0.34 = latexmath:[$\frac{34}{100}$] and
+0.567 = latexmath:[$\frac{567}{1000}$]. In some cases, you may be able
+to reduce that fraction. Because ``percent'' means ``out of 100'' the
+percent refers to the first two decimal places. Complete the code to ask
+for a decimal input, then print the fraction and the percent. Hint: The
+`exponent` variable gives you the number of decimal places.
+
+
++*In[24]:*+
+[source, ipython3]
+----
+import math
+
+digits = input("Enter a decimal number to convert: ")
+exponent = int(len(digits))-1
+n = float(digits)
+
+# Change the values of these three variables
+numerator = int(n*10**exponent)
+denominator = 10**exponent
+percent = (numerator/denominator)*100
+
+# Output - keep this
+print("The decimal is ", n)
+print("The fraction is ", numerator, "/", denominator)
+print("The percent is ", percent, " %")
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step22(n,numerator,denominator,percent,exponent)
+----
+
+
++*Out[24]:*+
+----
+Enter a decimal number to convert:  .3242
+
+The decimal is  0.3242
+The fraction is  3242 / 10000
+The percent is  32.42  %
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 23 - Defining a Function
+
+To execute a block of code with one command, define a function with the
+`def` command and the name of the function. Notice everything in the
+function is indented 4 spaces. Run the following code to see an example.
+Then change the function name to `fun()` and also change the name where
+you call the function. Run the code again.
+
+
++*In[25]:*+
+[source, ipython3]
+----
+# Define a function
+def fun():
+    print("This is in the function")
+
+# Other code not in the function
+print("This is outside the function")
+
+# Call the function
+fun()
+
+print("Back outside the function")
+
+# Only change code above this line
+import math_code_test_a as test
+test.step23(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[25]:*+
+----
+This is outside the function
+This is in the function
+Back outside the function
+ 
+Code test passed
+Go on to the next step
+----
+
+== Step 24 - Function with Input
+
+A function can take input (called an ``argument'') and do something with
+that input. Use `def` to define the function, and include a variable in
+the parentheses to represent the argument. Indent everything that is a
+part of the function. When calling the function, pass the argument to it
+in the parentheses. Run the following code to see this example. Then
+change the `input()` variable name to `nombre` and also change that
+variable name in the argument when you call the function. Run the code
+again.
+
+
++*In[26]:*+
+[source, ipython3]
+----
+# Define a function
+def greeting(name):
+    print("Hello ", name)
+
+nombre = input("What is your name? \n")
+
+# Call the function
+greeting(nombre)
+
+# Only change code above this line
+import math_code_test_a as test
+test.step24(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[26]:*+
+----
+What is your name? 
+ Python
+
+Hello  Python
+ 
+Code test passed
+You can go on to the next step
+----
+
+== Step 25 - Function with Two Inputs
+
+To pass more than one argument to a function, separate the arguments
+with commas. Run the code to see the example, then add a third argument
+to the function and run it again. The `third` variable is already in the
+code. Change three lines of code to use that variable: (1) the argument
+when you call the function, (2) the argument when you define the
+function, (3) the `sum` line within in the function definition.
+
+
++*In[50]:*+
+[source, ipython3]
+----
+# Define function
+def add(a,b, c):
+  # Use c for the third variable
+  sum = a+b+c
+  print("The sum is ", sum)
+
+first = float(input("Enter a number: \n"))
+second= float(input("Enter another number: \n"))
+third = 3
+
+# Call the function
+add(first,second, third)
+
+# Only change code above this line
+import math_code_test_a as test
+test.step25(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[50]:*+
+----
+Enter a number: 
+ 231
+Enter another number: 
+ 321
+
+The sum is  555.0
+ 
+Code test passed
+You can go on to the next step
+----
+
+== Step 26 - Function with Return Value
+
+Instead of including a `print()` statement within the function, the
+function can `return` a value right where you call it. To make the
+function return a value, use the `return` statement. Run the following
+code to see an example, then change the `return` statement to multiply
+by 3 instead of 2 and run the code again.
+
+
++*In[52]:*+
+[source, ipython3]
+----
+# define the function
+def multiplied(number):
+    return number*3
+
+a = float(input("Enter a number: \n"))
+print("Your number multiplied = ", multiplied(a))
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step26(In[-1].split('# Only change code above this line')[0])
+----
+
+
++*Out[52]:*+
+----
+Enter a number: 
+ 322
+
+Your number multiplied =  966.0
+ 
+Code test passed
+You can go on to the next step
+----
+
+== Step 27 - Solving for x
+
+In Algebra, `X` often refers to the unknown number in an equation. To
+find the value of `x` we use algebra rules to get to `x =` [some
+number]. SymPy is a Python library to work with symbolic math. The
+following code works to solve an equation set equal to zero. Run the
+code and remember to use Python syntax to enter an equation (with ``x''
+as the variable) and see the solution.
+
+
++*In[54]:*+
+[source, ipython3]
+----
+import sympy
+from sympy import symbols
+from sympy.solvers import solve
+
+x = symbols('x')
+
+eq = input('Enter an equation to solve for x: 0 = ')
+print(len(solve(eq,x)))
+print("x = ", solve(eq,x)[0])
+
+
+# Only change code above this line
+import math_code_test_a as test
+test.step27(In[-1].split('# Only change code above this line')[0])
+
+----
+
+
++*Out[54]:*+
+----
+Enter an equation to solve for x: 0 =  23*x**2 + 32*x + 2342
+
+2
+x =  -16/23 - sqrt(53610)*I/23
+If you didn't get a syntax error, you are ready for the project
+----
+
+== Step 28 - Make your own Functions
+
+Building upon what you did in previous steps, define a different
+function for each of the following:
+
+Add, subtract, multiply, divide
+
+Detect prime numbers
+
+Generate prime factors of a number
+
+Simplify square roots
+
+Solve for a variable
+
+Each function should prompt the user with a question, take input, and
+output the answer.
+
+
++*In[27]:*+
+[source, ipython3]
+----
+# Write your code here
+import re
+import sympy
+from sympy import symbols
+from sympy.solvers import solve
+
+def arithematic():
+    print("Enter an equation comprising only of numbers seprated by aithematic operators:")
+    eq = input()
+    if (re.search("^(\s?[0-9]+\s?[+-\\\*]\s?)+[0-9]+$", eq)):
+        result = eval(eq)
+        print(f'{eq} = {result}')
+    else:
+        print("Error: equation is not in accepted format")
+
+def get_smallest_prime_factor(num):
+    if (num % 2 == 0 and num != 2):
+        return 2
+    
+    for i in range(3, int(num/2)+1, 2):
+        if num % i == 0:
+            return i
+
+    return 1
+        
+def is_prime():
+    try:
+        num = int(input("Type a natural number to test if it a prime number:"))
+    except Exception as e:
+        print("Error:", e)
+        return
+        
+    smallest_prime_factor = get_smallest_prime_factor(num)
+    if (smallest_prime_factor == 1):
+        print(f"{num} is a prime number.")
+    else:
+        print(f"{num} is not a prime number and is divisible by {smallest_prime_factor}")
+
+def prime_factorization():
+    try:
+        num = int(input("Type a natural number to find it's prime factors:"))
+    except Exception as e:
+        print("Error:", e)
+    
+    factors = []
+    new_num = num
+    while True:
+        factor = get_smallest_prime_factor(new_num)
+        if (factor == 1):
+            factors.append(int(new_num))
+            break
+        else:
+            factors.append(factor)
+            new_num /= factor
+    print(f"Prime factors of {num} are:")
+    print(' x '.join([str(n) for n in factors]))
+
+def simplify_sqrt():
+    try:
+        sqrt = int(input("Input a radical/square root number (without symbol) to find it's simplified form:"))
+    except Exception as e:
+        print("Error:", e)
+        return
+    
+    maybe_factor = 2
+    max_factor = 1
+    while (maybe_factor**2 <= sqrt):
+        if (sqrt % maybe_factor**2 == 0):
+            max_factor = maybe_factor
+        maybe_factor += 1
+    return max_factor*sympy.sqrt(int(sqrt/max_factor**2))
+
+def solve_for_x():
+    try:
+        eq = input("Type an equation to solve for x. 0 = ")
+        x = symbols("x")
+        solutions = solve(eq, x)
+        for s in solutions:
+            print("x =", s)
+    except BaseException as e:
+        print(f"Error: {e}")
+
+# This step does not have test
+----
+
+== Step 29 - Create a Menu
+
+Use print statements to create a menu that displays a numbered list of
+options. Then prompt for user input to choose an option. Use an `if`
+statement to print a different message for each option in the menu.
+
+
++*In[28]:*+
+[source, ipython3]
+----
+# Write your code here
+from IPython.display import display
+
+options = [("Simple calculations", arithematic),
+           ("Check if a number is prime", is_prime),
+           ("Prime factorize a number", prime_factorization),
+           ("Find simplified form of a square root", simplify_sqrt),
+           ("Solve an euqation for X", solve_for_x)]
+
+def print_menu():
+    print("What would you like to do?")
+    for i in range(len(options)):
+        print(f"{i+1}: {options[i][0]}")
+
+# This step does not have test
+----
+
+== Step 30 - Certification Project 1
+
+Now put it all together to build a multi-function calculator. Use the
+menu and the functions you created in the previous steps. Define one
+more function of your own. Create the menu so that the user input will
+run a function.
+
+
++*In[29]:*+
+[source, ipython3]
+----
+# Write your code here
+
+print_menu()
+
+try:
+    selected = int(input())
+except BaseException as e:
+    print("Error:", e)
+if selected < 1 or selected > len(options):
+    print("Error: Invalid option selected")
+elif selected == 4: # for pretty printing sqrt symbol
+    display(options[selected-1][1]())
+else:
+    options[selected-1][1]()
+
+# This step does not have test
+----
+
+
++*Out[29]:*+
+----
+What would you like to do?
+1: Simple calculations
+2: Check if a number is prime
+3: Prime factorize a number
+4: Find simplified form of a square root
+5: Solve an euqation for X
+
+ 4
+Input a radical/square root number (without symbol) to find it's simplified form: 32
+4*sqrt(2)----
+
+
++*In[ ]:*+
+[source, ipython3]
+----
+
+----