Squares

A square number is a number that can be found by multiplying a number by itself. For instance, 36 is a square number because 6×6 = 36.

The verb to square can be used to refer to multiplying a number by itself. So we can square 6 to get 36.

We can use index notation to show this. We write 6²=36, where the 2 is called the power or the index and tells us that “2” 6s are multiplied together.

Exercise 1

Square Roots

The inverse of squaring a number is taking the square root of a number. So the square root of 36 is 6. We write this using this special symbol: √36 = 6. So what would √64 be?

Note that geometrically, the square root of a number means the length of a square which has that number as its area.

Exercise 2

Calculator use

Can you find the square root sign on your calculator. Using this can be an effective way of calculating the square root of a number. Can you use it to check what the square root of 196 is?

Exercise 3

Answers to all three exercises