Square Numbers

1
Square Numbers Area Models

• Unit One
• (sec. 1.1 1.2)
• Lesson 01
• Koomens Klass

2
2

• A square is a quadrilateral
• with four right angles and
• an equal number of units
• on every edge.

2

• When we multiply a number
• by itself, we square the
• number!

2 x 2 4
3
3 x 3 9
3
3
4
4 x 4 16
4
4
5
5 x 5 25
5
5
6
Square Numbers
2 x 2 4

• two times two equals four

• we say . . . two squared is four . . .

4 is a square number, or a PERFECT SQUARE
7
How can we determine whether or not a number is
square?
Write a division sentence so the quotient is
equal to the divisor.
When a number has an odd number of factors it is
square.
8
Square Roots
By definition Ö4 is the number you would
multiply times itself to get 4 for an answer.
Because we are familiar with multiplication, we
know that 2 x 2 4 so . . . Ö4 2
Numbers like 4, which have whole numbers for
their square roots, are called perfect squares
The number that you multiply by itself is called
the square root
9
2
The square root of 4 is
. . . because 2 x 2 4
10
3
The square root of 9 is
. . . because 3 x 3 9
11
4
The square root of 16 is
12
5
The square root of 25 is
13
You must memorize at least the first 15 perfect
square numbers and their corresponding roots ?
14
Square root
Square root
Perfect square
Perfect square
1
Ö1 1
81
Ö81 9
4
100
Ö4 2
Ö100 10
9
121
Ö9 3
Ö121 11
16
144
Ö16 4
Ö144 12
25
169
Ö25 5
Ö169 13
36
196
Ö36 6
Ö196 14
49
225
Ö49 7
Ö225 15
64
Ö64 8
15
PRACTICE. . .
text p. 9 (12 thru 17) p. 10
(20) p. 15 (9 thru 12)
p. 16 (17 thru 21)

• Show your work
• Check your answers