JavaScript Arithmetic

Arithmetic operators are used to perform mathematical calculations on numbers (literals or variables). From simple addition to complex power calculations, JavaScript provides a full set of tools to handle math inside your code.

Arithmetic Operators Table

Here are the most common arithmetic operators you will use in JavaScript:

Operands and Operators

In a mathematical expression, the numbers are called operands and the symbol representing the action is called the operator.

In the expression 10 + 5:

• 10 and 5 are operands.
• + is the operator.

Addition (+)

The addition operator adds numbers together.

let x = 10;
let y = 5;
let result = x + y; // result is 15

Subtraction (-)

The subtraction operator subtracts the second number from the first.

let x = 10;
let y = 5;
let result = x - y; // result is 5

Multiplication (*)

The multiplication operator multiplies two numbers.

let x = 10;
let y = 5;
let result = x * y; // result is 50

Exponentiation (**)

The exponentiation operator raises the first operand to the power of the second operand.

let x = 5;
let result = x ** 2; // result is 25 (5 squared)

Division (/)

The division operator divides the first number by the second.

let x = 10;
let y = 2;
let result = x / y; // result is 5

Modulus (%)

The modulus operator returns the remainder of a division. It is often used to check if a number is even or odd (e.g., x % 2 === 0).

let x = 10;
let y = 3;
let result = x % y; // result is 1 (10 divided by 3 leaves a remainder of 1)

Increment (++)

The increment operator increases a number by 1.

let x = 5;
x++; 
// x is now 6

Decrement (--)

The decrement operator decreases a number by 1.

let x = 5;
x--; 
// x is now 4

Operator Precedence

Operator precedence describes the order in which operations are performed in an arithmetic expression. Just like in school math, multiplication and division are performed before addition and subtraction (PEMDAS/BODMAS).

let result = 100 + 50 * 3; // result is 250, because 50 * 3 is done first

You can use parentheses () to force a different order of calculation:

let result = (100 + 50) * 3; // result is 450, because the addition happens first

Key Points to Remember

• Arithmetic operators perform math on numbers and variables
• The modulus operator % is great for finding remainders
• Exponentiation ** is a modern way to calculate powers
• Increment ++ and decrement -- are shortcuts to change values by 1
• Always follow operator precedence or use parentheses to control the flow