Arithmetic operators JS Home  <<  JS Reference  <<  Arithmetic

The JavaScript arithmetic operators are used to return a single numerical value from other numerical literals or variables.

Description

Arithmetic operators allow us to apply basic maths to a set of operands.

  • Operands can be numerical or string literals that evaluate to numeric.
  • Division by zero produces +Infinity or -Infinity dependant upon operand signage.

Basic Operators


Operator Description Example Result
+Addition var a = 10 + 5;
var a = 10 + '5';		 a = 15
a = 105 (string concatenation)
-Subtraction var a = 10 - '5'; a = 5
* Mutiplication var a = 10 * '5'; a = 50
/Division var a = 10 / '5'; a = 2
%Modulus var a = 10 % '5';
var a = 12 % '5';		 a = 0 (integer remainder)
a = 2 (integer remainder)

Increment and Decrement Operators


Operator Description Example Result
var++Post Increment var a = 0, b = 5;
var a = b++;		 a = 5 and b =6.
++varPre Increment var a = 0, b = 5;
var a = ++b;		 a = 6 and b = 6.
var--Post Decrement var a = 0, b = 5;
var a = b--;		 a = 5 and b = 4.
--varPre Decrement var a = 0, b = 5;
var a = --b;		 a = 4 and b = 4.

Unary Operators


Operator Description Example Result
unary+Plus var a = -5, b = 5;
var a = +b;		 a = 5 and b = 5.
unary-Minus var a = 5, b = 5;
var a = -b;		 a = -5 and b = 5.


Related Tutorials

JavaScript Basic Tutorials - Lesson 5 - Basic Maths Functions