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.

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

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

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

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

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

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

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

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

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

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

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

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.

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