Summary  
This chapter covers performing simple math operations in code using the +, - , * , and / operators for addition, subtraction, multiplication, and division.  

General domain of usage  
Calculating costs in retail pricing.

Python makes math operations simple and powerful. Use the following basic arithmetic operators:

- **Addition** (`+`)
- **Subtraction** (`-`)
- **Multiplication** (`*`)
- **Division** (`/`)

import unittest
import re
import importlib
from io import StringIO
from contextlib import redirect_stdout

def _dynamic_test(test_case, condition, success_message, failure_message):
    if condition:
        test_case._testMethodName = success_message
        test_case.assertTrue(True, success_message)
    else:
        test_case._testMethodName = failure_message
        test_case.fail(failure_message)

class TestUserCode(unittest.TestCase):

    def test_addition_operation_result_is_correct(self):
        # Test the first printed value: 5.42 + 4.39 should equal 9.81.
        import user_code  # The user solution file is named user_code.py
        output_capture = StringIO()
        with redirect_stdout(output_capture):
            importlib.reload(user_code)
        output = output_capture.getvalue().strip()
        lines = output.splitlines()

        if len(lines) < 1:
            _dynamic_test(
              self,
              False,
              "",
              "Missing addition result."
            )

        addition_result = lines[0].strip()

        expected_addition = str(5.42 + 4.39)  # Expected result: 9.81
        condition = addition_result == expected_addition

        _dynamic_test(
            self,
            condition,
            "Addition result is correct.",
            f"Expected addition result to be '{expected_addition}' but got '{lines[0].strip()}'."
        )

    def test_subtraction_operation_result_is_correct(self):
        # Test the second printed value: 12.30 - 5.50 should equal 6.8.
        import user_code
        output_capture = StringIO()
        with redirect_stdout(output_capture):
            importlib.reload(user_code)
        output = output_capture.getvalue().strip()
        lines = output.splitlines()

        if len(lines) < 2:
            _dynamic_test(
              self,
              False,
              "",
              "Missing subtraction result."
            )

        subtraction_result = lines[1].strip()
        expected_subtraction = str(12.30 - 5.50)  # Expected result: 6.8
        condition = subtraction_result == expected_subtraction

        _dynamic_test(
            self,
            condition,
            "Subtraction result is correct.",
            f"Expected subtraction result to be '{expected_subtraction}' but got '{lines[1].strip()}'."
        )

if __name__ == '__main__':
    unittest.main()


test_main.py

Python is a high-level, interpreted, general-purpose programming
language. Distinguished from languages such as HTML, CSS, and JavaScript, which are mainly
utilized in web development, Python boasts versatility across multiple domains, including
software development, data science, and back-end development. This course will guide you
through Python's fundamental concepts, equipping you with the skills to create your own
functions by the conclusion of the program.

In this section, you will explore the fundamentals of Python, get acquainted
with your workspace, perform simple math operations, and display your findings.

In this section, you'll discover how to save items such as numbers and text
in computer memory and retrieve them by name. Additionally, you'll gain an introduction to text
manipulation in Python.

In this section, you'll explore the boolean data type and learn how it is used
to develop programs that react to certain conditions.

In this section, you will continue learning about data types and discover
how to organize various attributes in a single variable using lists, tuples, and dictionaries.

In this section, you'll learn how to create loops in Python — an essential skill
for iterating through lists, tuples, and dictionaries.

To conclude this introductory course, you will explore some built-in
functions and then begin to develop your own!

Simple Math: Add & Subtract

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