Arithmetic operators

Learn basic arithmetic with +, -, *, / and %.

Arithmetic operators

In JavaScript, arithmetic operators perform basic math on numbers: + (addition), - (subtraction), * (multiplication), / (division) and % (modulo, remainder).

For example, 10 + 3 returns 13, 10 / 3 returns 3.333..., 10 % 3 returns 1. Modulo gives the remainder after division; very useful for odd/even checks.

These operators also work with variables: price * qty.

Modulo and exponent

The modulo operator is written with % and gives the remainder after division. For example, 7 % 3 returns 1 (7 = 2*3 + 1).

This is ideal for checking whether a number is odd or even: n % 2 === 0 means even, n % 2 === 1 means odd.

For exponentiation, use **: 2 ** 3 returns 8. In old code you may see Math.pow(2, 3).

Exercise Arithmetic calculation

Declare a = 10 and b = 3. Compute sum, product and remainder as a + b, a * b, a % b respectively. Print each with console.log.

Show example solution

const a = 10;
const b = 3;
const sum = a + b;
const product = a * b;
const remainder = a % b;
console.log(sum);
console.log(product);
console.log(remainder);

Test yourself

What does 7 % 3 return?
- 10
- 2.33
- 0
- 1
Show answer

1 — 7 = 2*3 + 1, remainder is 1.

Addition example

const sum = 10 ____ 5;

Show answer

const sum = 10 + 5;

Match the operators

+

Addition
-

Subtraction
*

Multiplication
%

Modulo (remainder)

Next lesson: Assignment operators

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