Chapter 1: Numbers, 1.2: Estimating Surds

Learn how to estimate square roots by using square numbers and consecutive integers to find the approximate value of a surd.

What is a surd?

An irrational number written using a square root symbol.

What is an example of a surd?

√2

What is √2 written as a surd?

√2

What is 5²?

25

What is 10²?

100

What is 15²?

225

What is 20²?

400

What are consecutive integers?

Whole numbers that come directly after one another, with a difference of 1.

Give an example of two consecutive integers.

4 and 5

What do you need to find when estimating a surd?

The two consecutive integers whose squares are on either side of the number.

What are the two consecutive integers around √20?

4 and 5

What is 4²?

16

What is 5²?

25

Is 20 between 16 and 25?

Yes

What is the range of √20?

4 < √20 < 5