Horizons Math Sampler - Odyssey Academy

Horizons Math 6 SAMPLE
Lesson 45
Square Roots
When a number has an exponent of 2, that number is said to be “squared.”
For example, 12 2 can also be written 12 x 12. 12 x 12 = 144. 4 2 can also be
written 4 x 4. 9 2 can also be written 9 x 9. These numbers are perfect squares
because they can be illustrated as shown below.
12 x 12 = 144 4 x 4 = 16 9 x 9 = 81
Suppose you were given the number 144 and asked which number multiplied by
itself equals 144? Your answer would be 12, because 12 2 = 144. Therefore, 12 is
the square root of 144. What would be the square root of 16? 4 would be the
square root of 16. What would be the square root of 81? 9 would be the square
root of 81.
To find the square root of a given number, you have to make an educated guess
based on your knowledge of the multiplication tables. Suppose you are given
the number 64. Think through your multiplication tables. Which number,
multiplied by itself, will yield an answer close to 64? 7 x 7 = 49, so it must be a
number larger than 7. 10 x 10 is 100, so it must be a number lower than 10.
8 x 8 = 64, so 8 2 = 64.
1
Complete the table. The first one is done for you.
Number
121
196
25
225
Square Root
11
23
4
Multiplication
Problem
11 x 11 = 121 or 11 2
55