6

Whole numbers Square root of numbers up to their digits

Definition of a perfect square

A perfect square is a number that can be expressed as a product of two equal integers

Examples of perfect squares

1=1×1

4=2×2

9=3×3

16=4×4

The numbers:

1,4,9and 16 are examples of perfect squares.

Look at the images below

Four

Nine

How to work out the square root of a number

 Step1: Express the number as a product of its prime factors. Example

81=3×3×3×3

Step:2

Pair the prime factors

(3×3) (3×3)

Step:3

picks one number from each pair

 (3×3) -----3

(3×3)------3

 Step:4 find the product of the Numbers picked from each pair.   3×3= 9

9 is the square root of 81

More examples: find the square root of

 100

100 =2×2×5×5

(2×2)(5×5)

2×5=10

10 is the square root of 100

625

625=5×5×5×5

(5×5)(5×5)

5×5=25

25 is the square root of 625

Exercise: find the square root of the numbers below

1.(a)64

   (b) 25

   (c)36

   (d)121

2.(a)625

   (b)900

   (c)144

   (d)169

Answers

1,(a) 8 (b)5  (c) 6 (d)11

2(a) 25 (b) 30 (c) 12 (d) 13