JavaScript Operators

Numeric data in JavaScript is represented by the Number data type.

Add Two Numbers

In JavaScript, like in mathematics, the + symbol is used as an addition operator when in between two number.

Example:

var randomNumber = 7 + 10; // 17

Subtract One Number from Another

JavaScript uses the - symbol for subtraction, in order to subtract one number from another:

var randomNumber = 10 - 5; // 5

Multiply Two Numbers

JavaScript uses the * symbol for multiplication of two numbers:

var randomNumber = 10 * 10; // 100

Divide One Number by Another

JavaScript uses the / symbol in order to divide one number by another:

var randomNumber = 100 / 10; // 10

Increment a Number

In JavaScript, we can use the ++ operator to increment or add one to a variable:

i++;

is the equivalent of

i = i + 1;

Decrement a Number

In JavaScript, we can use the -- operator to decrement or decrease a variable value by one:

i--;

is the equivalent of

i = i - 1;

Create Decimal Numbers

Variables can store also decimal number, which are referred to also as floating point numbers or simply floats.

var myDecimal = 9.9;

Multiply Two Decimals

Just like with whole numbers, in JavaScript, we can perform calculations also with decimal numbers:

var product = 2.0 * 2.5; // 5

Divide One Decimal by Another

Now let’s divide one decimal by another:

var quotient = 6.6 / 2.0; // 3.3

Finding a Remainder

In programming, it’s common to check if a number is even (divisible by 2) or odd (not divisible by 2).

The remainder operator % gives the remainder of the division of two numbers:

17 % 2 = 1; // 17 ==> Odd
10 % 2 = 0; // 10 ==> Even

We can break this down by:

Math.floor(17 / 2) = 8;
8 * 2 = 16;
17 - 16 = 1; // Remainder

Compound Assignment With Augmented Addition

In programming, we use assignments to modify the content of a variable. Moreover, other than assigning a new value, we saw also how to perform basic mathematical operation.

In JavaScript, we can combine a mathematical operator and the assignment operator and obtain a new operator used for augmented addition +=:

var myFavoriteNumber = 1;
myFavoriteNumber += 16;
console.log(myFavoriteNumber); // 17

Compound Assignment With Augmented Subtraction

Just like the += operator we saw before, -= subtracts a number from a variable:

var myFavoriteNumber = 4;
myFavoriteNumber -= 1;
console.log(myFavoriteNumber); // 3

Compound Assignment With Augmented Multiplication

Using the *= operator, we can multiply a variable by a number:

var myFavoriteNumber = 5;
myFavoriteNumber *= 6;
console.log(myFavoriteNumber); // 30

Compound Assignment With Augmented Division

Using the /= operator, we can divide a variable by another number:

var myFavoriteNumber = 10;
myFavoriteNumber /= 2;
console.log(myFavoriteNumber); // 5