Day 6: Create a Simple Python Calculator in 3 Easy Steps | Master Python in 100 Days

Day 6: Creating a Calculator in Python

Welcome to Day 6 of our "Master Python in 100 Days" series! Today, we are going to build a simple calculator using Python. This exercise will teach you how to work with basic mathematical operators in Python while also giving you a chance to write your own code from scratch.

What Are Operators in Python?

• Before we jump into the code, let’s talk about operators in Python. Operators are special symbols used to perform operations on variables and values. You’ve already seen them in mathematics. In Python, we have the same kind of operators that we use to add, subtract, multiply, and divide numbers.

Let me explain these operators in a simple way:

• Addition (+): Adds two numbers.

          Example: 5 + 3 = 8

• Subtraction (-): Subtracts one number from another.

          Example: 10 - 4 = 6

• Multiplication (*): Multiplies two numbers.

          Example: 6 * 7 = 42

• Division (/): Divides one number by another and returns the result as a floating-point number (decimal).

          Example: 15 / 4 = 3.75

• Floor Division (//): Divides and gives the whole number part only (ignores decimals).

          Example: 15 // 4 = 3

• Modulus (%): Returns the remainder of the division of one number by another.

          Example: 15 % 4 = 3 (because 15 divided by 4 gives a remainder of 3)

• Exponentiation ()**: Raises one number to the power of another.

          Example: 5 ** 2 = 25 (which means 5² or 5 * 5)

Task: Create a Simple Calculator

• Now, we know the operators, let’s move on to creating our own calculator! We will write a Python program that takes two numbers from the user and performs the four basic operations: addition, subtraction, multiplication, and division.

Step-by-Step Breakdown:

1. Taking User Input

First, we need two numbers from the user. To take input in Python, we use the input() function. Since the input() function always takes input as a string, we have to convert the input into integers or floats, depending on the kind of numbers we want to work with.

Here, float() is used to convert the input into a decimal number. We could also use int() if we only wanted whole numbers.

2. Performing the Operations

Now, we will perform the basic arithmetic operations on the two numbers using Python’s built-in operators. We will store the results in variables so we can display them later.

3. Displaying the Results

Finally, we need to print out the results so the user can see the output of each operation.

We’re using formatted strings (f"{num1} + {num2} = {addition}") to make the output more readable.

Now, Let's Add These Three Steps and Write the Full Code

How the Code Works:

• User Input: We first take two numbers from the user using input(). These are stored in num1 and num2. Since the input is taken as a string by default, we convert it into float to handle both whole and decimal numbers.

• Operations: We then perform the four operations (addition, subtraction, multiplication, and division) on these numbers and store the results in separate variables.

• Displaying Results: Finally, we print out the results of each operation using the print() function. We use an f-string to format the output, which is a simple and clean way to display variables inside strings.

Key Points 

• Basic Python Operators: We covered how to use simple math operators like addition (+), subtraction (-), multiplication (*), and division (/). These help us in doing math calculations easily.

• Floor Division and Modulus: We learned how to use floor division (//) which gives only the whole number part of a division, and modulus (%) which gives the remainder of a division.

• Exponential Operator: The double asterisk (**) is used to calculate powers. For example, 5**3 means 5 raised to the power of 3, which is 555.

• Creating a Simple Calculator: We applied these operators to make a calculator that can add, subtract, multiply, and divide two numbers.

That’s it for Day 6! Practice this exercise and try adding more features to your calculator. For example, you could allow the user to select which operation they want to perform instead of doing all of them every time.

Tomorrow, we’ll go over more exciting Python concepts, so stay tuned! Keep practicing, and see you in the next lesson!