---
title: Arithmetic Operation
---
JavaScript provides the user with five arithmetic operators: `+`, `-`, `*`, `/` and `%`. The operators are for addition, subtraction, multiplication, division and remainder respectively.
## Addition
**Syntax**
`a + b`
**Usage**
2 + 3 // returns 5
true + 2 // interprets true as 1 and returns 3
false + 5 // interprets false as 0 and returns 5
true + "bar" // concatenates the boolean value and returns "truebar"
5 + "foo" // concatenates the string and the number and returns "5foo"
"foo" + "bar" // concatenates the strings and returns "foobar"
_Hint:_ There is a handy increment) operator that is a great shortcut when you're adding numbers by 1.
## Subtraction
**Syntax**
`a - b`
**Usage**
2 - 3 // returns -1
3 - 2 // returns 1
false - 5 // interprets false as 0 and returns -5
true - 3 // interprets true as 1 and returns -2
5 - "foo" // returns NaN (Not a Number)
_Hint:_ There is a handy decrement) operator that is a great shortcut when you're subtracting numbers by 1.
## Multiplication
**Syntax**
`a * b`
**Usage**
2 * 3 // returns 6
3 * -2 // returns -6
false * 5 // interprets false as 0 and returns 0
true * 3 // interprets true as 1 and returns 3
5 * "foo" // returns NaN (Not a Number)
Infinity * 0 // returns NaN
Infinity * Infinity // returns Infinity
## Division
**Syntax**
`a / b`
**Usage**
3 / 2 // returns 1.5
3.0 / 2/0 // returns 1.5
3 / 0 // returns Infinity
3.0 / 0.0 // returns Infinity
-3 / 0 // returns -Infinity
false / 5 // interprets false as 0 and returns 0
true / 2 // interprets true a 1 and returns 0.5
5 / "foo" // returns NaN (Not a Number)
Infinity / Infinity // returns NaN
## Remainder
**Syntax**
`a % b`
**Usage**
3 % 2 // returns 1
true % 5 // interprets true as 1 and returns 1
false % 4 // interprets false as 0 and returns 0
3 % "bar" // returns NaN
## Increment
**Syntax**
`a++ or ++a`
**Usage**
// Postfix
x = 3; // declare a variable
y = x++; // y = 4, x = 3
// Prefix
var a = 2;
b = ++a; // a = 3, b = 3
## Decrement
**Syntax**
`a-- or --a`
**Usage**
// Postfix
x = 3; // declare a variable
y = x--; // y = 3, x = 3
// Prefix
var a = 2;
b = --a; // a = 1, b = 1
_!Important!_ As you can see, you **cannot** perform any sort of operations on `Infinity`.
Source: The amazing MDN.