JavaScript | Arithmetic Operators

JavaScript Arithmetic Operators are the operators that operate upon the numerical values and return a numerical value. There are many operators in JavaScript. Each operator is described below along with its example.

1. Addition (+) The addition operator takes two numerical operands and gives their numerical sum. It also concatenates two strings or numbers.

Syntax:

a + b

Example:

// Number + Number => Addition 
1 + 2 gives 3

// Number + String => Concatenation
5 + "hello" gives "5Hello"

2. Subtraction (-) The subtraction operator gives the difference of two operands in the form of numerical value.

Syntax:

a - b

Example:

// Number - Number => Subtraction 
10 - 7 gives 3

"Hello" - 1 gives Nan

3. Multiplication (*) The multiplication operator gives the product of operands where one operand is multiplicand and another is multiplier.

Syntax:

a * b

Example:

// Number * Number => Multiplication
3 * 3 gives 9
-4 * 4 gives -16

Infinity * 0 gives NaN
Infinity * Infinity gives Infinity
'hi' * 2 gives NaN

4. Division (/) The division operator provides the quotient of its operands where the right operand is the divisor and the left operand is the dividend.

Syntax: 

a / b

Example:

// Number / Number => Division
5 / 2 gives 2.5
1.0 / 2.0 gives 0.5

3.0 / 0 gives Infinity
4.0 / 0.0 gives Infinity, because 0.0 == 0
2.0 / -0.0 gives -Infinity

5. Modulus (%) The modulus operator returns the remainder left over when a dividend is divided by a divisor. The modulus operator is also known as remainder operator. It takes the sign of the dividend.

Syntax:

a % b

Example:

// Number % Number => Modulus of the number

9 % 5 gives 4
-12 % 5 gives -2
1 % -2 gives 1
5.5 % 2 gives 1.5
-4 % 2 gives -0

NaN % 2 gives NaN

6. Exponentiation (**) The exponentiation operator gives the result of raising the first operand to the power of the second operand. The exponentiation operator is right-associative. 

Syntax:

a ** b

In JavaScript, it is not possible to write an ambiguous exponentiation expression i.e. you cannot put an unary operator (+ / – / ~ / ! / delete / void) immediately before the base number.

Example:

// Number ** Number => Exponential of the number

-4 ** 2 // This is an incorrect expression
-(4 ** 2) gives -16, this is a correct expression
2 ** 5 gives 32
3 ** 3 gives 27
3 ** 2.5 gives 15.588457268119896
10 ** -2 gives 0.01
2 ** 3 ** 2 gives 512
 
NaN ** 2 gives NaN

7. Increment (++) The increment operator increments (adds one to) its operand and returns a value.

• If used postfix  with operator after operand (for example, x++), then it increments and returns the value before incrementing.
• If used prefix with operator before operand (for example, ++x), then it increments and returns the value after incrementing.

Syntax: 

a++ or ++a

Example:

// Postfix 
var a = 2;
b = a++; // b = 2, a = 3

// Prefix
var x = 5;
y = ++x; // x = 6, y = 6

8. Decrement (–) The decrement operator decrements (subtracts one from) its operand and returns a value.

• If used postfix, with operator after operand (for example, x–), then it decrements and returns the value before decrementing.
• If used prefix, with operator before operand (for example, –x), then it decrements and returns the value after decrementing.

Syntax:

a-- or --a

Example:

// Prefix
var x = 2;
y = --x; gives x = 1, y = 1

// Postfix 
var x = 3;
y = x--; gives y = 3, x = 2

9. Unary (-) This is a unary operator i.e. it operates on a single operand. It gives the negation of an operand.

Syntax:

-a

Example:

var a = 3;
b = -a; gives b = -3, a = 3

// Unary negation operator
// can convert non-numbers
// into a number
var a = "3";
b = -a; gives b = -3

10. Unary (+) This is a way to convert a non-number into a number. Although unary negation (-) also can convert non-numbers, unary plus is the fastest and preferred way of converting something into a number, because it does not perform any other operations on the number.

Syntax:

+a

Example:

+4     gives 4
+'2'   gives 2
+true  gives 1
+false gives 0
+null  gives 0