JavaScript Arithmetic Operators


What Are Arithmetic Operators?

Arithmetic operators in JavaScript are used to perform mathematical calculations on numbers. They work with both integer and floating-point values.


List of Arithmetic Operators

Operator Name Description Example Output
+ Addition Adds two operands 5 + 3 8
- Subtraction Subtracts right operand from left 10 - 4 6
* Multiplication Multiplies two operands 2 * 6 12
/ Division Divides left operand by right 12 / 4 3
% Modulus Returns remainder of division 10 % 3 1
** Exponentiation Raises left operand to the power of right 2 ** 3 8
++ Increment Increases value by one (prefix/postfix) ++a or a++ a+1
-- Decrement Decreases value by one (prefix/postfix) --a or a-- a-1

1. Addition (+)

let x = 5;
let y = 3;
console.log(x + y); // Output: 8

2. Subtraction (-)

let a = 10;
let b = 6;
console.log(a - b); // Output: 4

3. Multiplication (*)

let p = 7;
let q = 4;
console.log(p * q); // Output: 28

4. Division (/)

let result = 20 / 5;
console.log(result); // Output: 4

5. Modulus (%)

let mod = 10 % 4;
console.log(mod); // Output: 2

6. Exponentiation (**)

let power = 2 ** 3;
console.log(power); // Output: 8

7. Increment (++)

let num = 5;
console.log(++num); // Output: 6 (increments first, then returns)

Postfix

let num2 = 5;
console.log(num2++); // Output: 5 (returns first, then increments)
console.log(num2); // Output: 6

8. Decrement (--)


Prefix

let count = 3;
console.log(--count); // Output: 2

Postfix

let count2 = 3;
console.log(count2--); // Output: 3
console.log(count2); // Output: 2

Arithmetic with Strings

console.log("10" + 5); // Output: "105" (string concatenation)
console.log("10"- 2); // Output: 8 (string converted to number)

The + operator behaves differently if one operand is a string. It performs concatenation instead of addition.


Recap

Operation Symbol Example Output
Add + 4 + 2 6
Subtract - 5 - 3 2
Multiply * 3 * 3 9
Divide / 10 / 2 5
Remainder % 9 % 4 1
Power ** 2 ** 3 8
Increment ++ ++a a+1
Decrement -- --a a-1