Divisibility Rules

How do we know when we can divide one number into another

exactly?

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Vocabulary Divide: sharing or grouping a number into

equal parts

Divisible: can be divided without a remainder

Remainder: amount leftover after dividing a number

More Vocabulary

Quotient: the result of dividing one number by another (the answer)

Even: divisible by two – Ends with: 0; 2; 4; 6; 8

Odd: not divisible by two– Ends with: 1; 3; 5; 7; 9

More Vocabulary

Sum: total or whole amount (answer when adding)

Digit: symbol used to show a number– For example: 8; 16; 856

Divisibility Rules (2)

A number can be divided by 2 if

the last digit is even

– For example 52

Divisibility Rules (3)

a number is divisible by 3 if

the sum of the digits is 3, 6 or 9– For example

• 36– 3 + 6 = 9

– 9 ÷ 3 = 3

Divisibility Rules (4)

a number is divisible by 4 if

the number made by the last two digits can be divided by 4

Divisibility Rules (5)

A number is divisible by 5 if

the last digit is a 5 or a 0– For example

–75

– 90

Divisibility Rules (6)

A number can be divided by 6 if

the last digit is even and the sum of all the digits is 3, 6 or 9– For example

• 126– 1 + 2 + 6 = 9

– 9 ÷ 3 = 3

Divisibility Rules (8)

A number is divisible by 8 if

the number made by the last three digits will be divisible by 8– For example

• 152– 1 + 5 + 2 = 8

– 8 ÷ 8 = 1

Divisibility Rules (9)

A number is divisible by 9 if

the sum of all the digits will add to 9

Divisibility Rules (10)

A number can be divided by 10 if

the last digit is a 0– For example

• 60

Divisibility Rules

A number can be divided by 7 if

……………… can you find a rule?

Divisibility Rules

2, the last digit will be an even number

3, all the digits will add to 3,6 or 9

4, the number made by the last two digits can be divided by 4

5, the last digit will be a 5 or 0

Divisibility Rules

6, the last digit will be even and the digits will add to 3, 6 or 9

8, the number made by the last three digits will be divisible by 8

Divisibility Rules

9, the sum of the digits will be 9

10, the last digit will be a 0

There is no easy test for 7, although some methods have been invented, however it is easier to use a pencil and paper method.

Take the Quiz

Take the Quizhttp://www.softschools.com/quizzes/math/divisibility_rules/quiz3261.html

Divisibility Rules

Apply these rules to theses numbers: 74,673,042 444,555,448 61,616,168 732,510 66,666,666 179,131,590