Operators and expressions

Arithmetic operators

Javascript provides several arithmetic operators that let you perform mathematical calculations.

Symbol	Name	Description
+	Addition	Adds two values
-	Subtraction	Finds the difference between two values
*	Multiplication	Multiplies two values
/	Division	Divides one value by another
**	Exponentiation	Raises one value to the power of another
%	Remainder	Calculates the remainder on division

Expressions

An expression in javascript is a collection of operators and variables that evaluates down to a single value.

js

const bookPrice = 15 // variable
const numberOfBooks = 100 // variable
const totalValue = bookPrice * numberOfBooks // expression

console.log(totalValue)

output

1500

Modifying a variable

When updating a variable, we can use its old value to calculate its new value.

js

let availableBooks = 120
availableBooks = availableBooks + 10

console.log(availableBooks)

output

130

We can do this a bit more quickly with += and -=.

js

let availableBooks = 120

availableBooks += 10
console.log(availableBooks)

availableBooks -= 5
console.log(availableBooks)

output

130
125