Arithmetic - Divisibility Rules Flashcards Preview

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Flashcards in Arithmetic - Divisibility Rules Deck (12)
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1

dividing by 2

last digit is even

2

dividing by 3

the sum of the digits is divisible by 3
Example: 3 + 8 + 1 = 12 and 12 / 3 = 4

3

dividing by 4

the last two digits of the number are divisible by 4
Example: 1312 and 12 / 4 =3

4

dividing by 5

if the last digit is a 5 or a 0, then the number is divisible by 5

5

dividing by 6

if the number is divisible by both 3 and 2, it is divisible by 6

6

dividing by 7

take the last digit, double it, and subtract it from the remaining digits, if the answer is 0 or 7 it is divisible by 7

you can apply this rule to the answer again

Example:
2016
6 x 2 = 12
201 - 12 = 189
9 x 2 = 18
18 - 18 = 0

7

dividing by 8

the last three digits are divisible by 8
Example: 109816
816 / 8 = 102

8

dividing by 9

if the sum of the digits is divisible by 9
Example: 12348
1 + 2 + 3 + 4 + 8 = 18
18 / 9 = 2

9

dividing by 10

if the number ends in 0

10

dividing by 11

if you sum every second digit and then subtract all other digits and the answer is 0 or divisible by 11
Example: 1364
1 + 6 = 7
3 + 4 = 7
7 - 7 =0

11

dividing by 12

if the number is divisible by both 3 and 4

12

dividing by 13

-delete the last digit from the given number
-subtract nine times the deleted digit from the remaining digits
-if what is left is divisible by 13 then so is the original
-Example: 104
4 x 9 = 36
10 - 36 = -26
-26 / 13 =-2