Number and Number Sense

Number and Number Sense

Grade 3

Odd and Even Numbers

​Equal or not?

Multiple Choice

Are these two pictures equal?

• Yes

• No

What you have to remember:

Odd numbers

Odd numbers are numbers that when divided by 2, there is a remainder of 1.

​

example: 5 ​÷ 2 = 2 r. 1

7 ÷​ 2 = 2 r. 1

What you have to remember:

Even numbers

To easily remember, look at the last digit. End numbers end in 0, 2, 4, 6, or 8.​

What you have to remember:

Even numbers

Even numbers are numbers that when divided by 2, there is no remainder.

​

example: 4​÷ 2 = 2

6÷​ 2 = 3

What you have to remember:

Odd numbers

To easily remember, look at the last digit. Odd numbers end in 1, 3, 5, 7, or 9. ​

Multiple Choice

Odd or Even.

10

• odd

• even

Multiple Choice

Odd or Even.

19

• odd

• even

Multiple Choice

Odd or Even.

24

• odd

• even

Multiple Choice

Odd or Even.

816

• odd

• even

Multiple Choice

Odd or Even.

535

• odd

• even

Divisibility Rules

Divisibility Rules

​

Divisibility Rule for 2

Anumber is divisible by 2 if the number is EVEN.

​64. Is it divisible by 2? Look at the last digit. 4 is an even number, therefore the answer is yes! 64 is divisible by 2.

Multiple Choice

Is the following number divisible by 2?

546

• yes

• no

Multiple Choice

Is the following number divisible by 2?

413

• yes

• no

Multiple Choice

Is the following number divisible by 2?

1256

• yes

• no

Divisibility Rule for 4

A number is divisible by 4 if the last two digit is divisible by 4.

​8,512. Is it divisible by 4? Look at the last two digit. 12 ÷ 4= 3, therefore the answer is yes! 8,512 is divisible by 4.

Multiple Choice

Is the following number divisible by 4?

316

• yes

• no

Multiple Choice

Is the following number divisible by 4?

561

• yes

• no

Multiple Choice

Is the following number divisible by 4?

1320

• yes

• no

Divisibility Rule for 5

A number is divisible by 5 if the last digit ends in 0 or 5.

​420. Is it divisible by 5 Look at the last digit. It end with 0, therefore the answer is yes! 420 is divisible by 5.

Multiple Choice

Is the following number divisible by 5?

1326

• yes

• no

Multiple Choice

Is the following number divisible by 5?

23, 425

• yes

• no

Multiple Choice

Is the following number divisible by 5?

850

• yes

• no

Divisibility Rule for 9

A number is divisible by 9 if the sum of the digits is divisible by 9.

711​. Is it divisible by 9? Let's add the digits: 7+1+1= 9, 9 is divisible by 9, therefore the answer is yes! 711 is divisible by 9.

Multiple Choice

Is the following number divisible by 9?

93

• yes

• no

Multiple Choice

Is the following number divisible by 9?

108

• yes

• no

Multiple Choice

Is the following number divisible by 9?

234

• yes

• no

Divisibility Rule for 10

A number is divisible by 10 if the last digit is 0.

560​. Is it divisible by 10? Let's look at the last digit. Is it 0? therefore the answer is yes! 560 is divisible by 10.

Multiple Choice

Is the following number divisible by 10?

2310

• yes

• no

Multiple Choice

Is the following number divisible by 10?

2567

• yes

• no

Multiple Choice

Is the following number divisible by 10?

25,480

• yes

• no

GCF and LCM

GCF

Greatest Common Factor​

• list down the factors

• the biggest number that can divide the two numbers without a remainder is the GCF.​

GCF

What is the GCF of ​12 and 18

​Factors are the values that divide the original number into equal parts or numbers.

​

How to get it? List down numbers from 1-12, and 1-18. ​Check which number could divide 12 and 18 into equal parts.

​

​

GCF

What is the GCF of ​12 and 18

​12/1 = 12 12/ 10= 1r.2

12/2= 6 12/11= 1r.1

12/3= 4 12/12= 1

12/4= 3

12/5= 2r. 2​

​12/6= 2

​12/7= 1r. 5

12/8= 1r.​4

12/9= 1r.3​

​

​

​

​Factors of 12: ​1, 2, 3, 4, 6, 12

Factors of 18: ​1, 2, 3, 6, 9, 18

​

​

​Look for the common factor. The common factor is 6. Therefore, the GCF of 12 and 18 is 6.

GCF

What is the GCF of ​6 and 8

​Factors of 6: ​1, 2, 3, 6

Factors of 8: ​1, 2, 4, 8

​

​

​Look for the common factor. The common factor is 2. Therefore, the GCF of 6 and 8 is 2.

GCF

What is the GCF of ​40 and 60

​Factors of 40: ​1, 2, 3, 4, 5, 8, 10, 20, 40

Factors of 60: ​1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60

​

​

​Look for the common factors. The common factor are 1, 2, 3, 4, 5, 10, 20. Find the biggest factor. Therefore, the GCF of 40 and 60 is 20.

Multiple Choice

FInd the GCF of 20 and 30.

• 5

• 10

Multiple Choice

FInd the GCF of 18 and 27

• 3

• 9

LCM

Least Common Multiples

• list down the multiples

• the smallest common number that can divide the two numbers without a remainder is the LCM.

LCM

What is the LCM of 6 and 8?

multiples of 6: 6, 12, 18, 24, 36, 48, ...

multiples of 8: 8, 16, 24, 32, 40, 48, ...

​

We could stop listing multiples once we reach the smallest common multiple for both numbers. In the above numbers, we have 48 as the LCM of 6 and 8. ​

Fill in the Blanks

FInd the LCM of 12 and 15

Fill in the Blanks

FInd the LCM of 9 and 12