Divisibility rules

1. Divisibility Rules
How do we know when we can
divide one number into another
exactly?

2. PPT File Name: F:TeachingNorth East Carolina Prep School2013 - 2014FourthMathLesson PlansDivisibility Rules
PPT URL: http://tinyurl.com/powcp68
Notes URL: http://tinyurl.com/mmmx6l7

3. Vocabulary
Divide: sharing or grouping a number into
equal parts
Divisible: can be divided without a
remainder
Remainder: amount leftover after dividing a
number

4. 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

5. More Vocabulary
Sum: total or whole amount (answer when
adding)
Digit: symbol used to show a number
– For example: 8; 16; 856

6. Divisibility Rules (2)
A number can be
divided by 2 if
the last digit is even
– For example 52

7. 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

8. Divisibility Rules (4)
a number is divisible
by 4 if
the number made by
the last two digits can
be divided by 4

9. Divisibility Rules (5)
A number is divisible
by 5 if
the last digit is a 5 or a
0
– For example
7
5
– 9
0
–

10. 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

11. 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

12. Divisibility Rules (9)
A number is divisible
by 9 if
the sum of all the
digits will add to 9

13. Divisibility Rules (10)
A number can be
divided by 10 if
the last digit is a 0
– For example
• 6
0

14. Divisibility Rules
A number can be
divided by 7 if
……………… can
you find a rule?

15. 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

16. 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

17. 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.

18. Take the Quiz
Take the Quiz
http://www.softschools.com/quizzes/math/divisibility_rules/qui

19. 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