Numbers & Arithmetic Operations

Part 1

Python as a calculator

Python can perform mathematical calculations directly in your program. You can use numbers with arithmetic operators and store the results in variables.

print(10 + 5)
print(20 - 8)
print(5 * 4)
print(20 / 5)

Addition — +

The plus operator adds two or more numeric values.

a = 25
b = 15

total = a + b

print(total)

Subtraction — -

The minus operator subtracts one value from another.

print(100 - 35)

Multiplication — *

Python uses an asterisk (*) for multiplication.

price = 500
quantity = 4

total = price * quantity

print(total)

Division — /

The slash operator performs division. In Python, normal division with / produces a floating-point result.

print(20 / 5)

Important operator

Modulus — %

The modulus operator returns the remainder after division.

print(17 % 5)

Floor division — //

Floor division divides two numbers and returns the floor of the result.

print(17 // 5)

Exponentiation — **

The ** operator raises a number to a power.

print(2 ** 3)

Predict the output

Combine operators

result = 10 + 5 * 2
print(result)

Order of operations

Python follows the usual mathematical order of operations. Multiplication and division are performed before addition and subtraction unless parentheses change the order.

Arithmetic with variables

price = 250
quantity = 4
discount = 100

total = price * quantity
final_price = total - discount

print(final_price)

Your turn

Complete the expressions

Debug the calculation

price = 100
quantity = 3

total = price x quantity

print(total)

Real-world practice

Calculate a shopping bill

Suppose a customer buys 3 notebooks for ₹80 each. Use variables and multiplication to calculate the total.

price = 80
quantity = 3

total = price * quantity

print(total)