Numbers and math

Numbers

JavaScript has one kind of number. It can be a whole number such as 12, or a decimal number such as 4.8. You write a number without quotation marks.

Operators

An operator is a symbol that does something with values.

Operator	What it does	Example	Result
+	add	7 + 2	9
-	subtract	7 - 2	5
*	multiply	7 * 2	14
/	divide	7 / 2	3.5
%	remainder after division	7 % 2	1
**	power	7 ** 2	49

JavaScript does multiplication and division before addition and subtraction. Use parentheses to change the order: (1 + 2) * 3 is 9, and 1 + 2 * 3 is 7.

const width = 4;
const height = 3;
const area = width * height;
console.log(area);

The Math object

Math has functions for common jobs.

• Math.round(4.6) gives 5. It rounds to the nearest whole number.
• Math.floor(4.6) gives 4. It rounds down.
• Math.ceil(4.2) gives 5. It rounds up.
• Math.max(3, 9, 5) gives 9. It finds the largest value.

Your turn

Do the five tasks in order. Each task is checked on its own.