How to square root a number (eg √9=3). Math help.

To find the square root of a number all you need to do is to look for a number when multiplied by itself, which gives you the number that you are rooting.  Square roots and squares are opposite operations, so if you now your square numbers well enough, square roots should be straightforward to carry out.

Example 1

Find the square root of 64.

So we are looking for a number when multiplied by itself that gives 64.

The number we are looking for is 8, because 8 × 8 = 64

Example 2

Work out √49.

The symbol that is before 49 is basically a square root sign. So we need to find the square root of 49.

Again, try to think of number when multiplied by itself gives 49.

The answer is 7, as 7 × 7 = 49

Example 3

Work out √9.

All you have to do is the same as before, and look for a number when multiplied by itself which gives 9. Be careful not to square 9, as this gives 81.

The answer is therefore 3 as 3 × 3 = 9.

Sometimes we will need a calculator to find a square root, as our answer will not be a whole number.

Example 4

Work out the square root of 157.

Well we know that, 12 × 12 = 144 and 13 × 13 = 169, so our answer is going to be a decimal answer somewhere between 12 and 13.

In order to work this out, we will need a calculator (just use the root button √)

So the √157 = 12.53 (2 dp)

Extra Tips

To find the square root of a number all you need to do is look for a number when multiplied by itself which gives you the number that you are rooting.

Make sure you are rooting the number, and not squaring the number! When you are square rooting a number, the answer is always going to be smaller than the number that you started off with.

You won’t be able to square root a negative number.

The square root of 1 is 1.