1. Learn: To use divisibility rules

2. These rules let you test if one number can be evenly divided by another, without having to do too much calculation!

3.  Divisible- Can be divided by a number without leaving a remainder.  Composite Number- Numbers that are divisible by more than two numbers  Prime Numbers- Is a number that is divisible by only numbers 1 and itself.

4. Divisibility rules can be used:  to find out if a number is prime or composite  to help find factors of a number  to find GCF and LCM when dealing with fractions

5. A number is divisible by 2, if the ones digit is divisible by 2 For example: 746 is divisible by 2 … because 6 is divisible by 2 6 ÷ 2=3 (hint: any even # is divisible by 2!)

6. A number is divisible by 3, if the sum of the digits is divisible by 3 For example: 12,321 is divisible by 3 … because 1+2+3+2+1=9 9 is divisible by 3 9÷3=3

7. A number is divisible by 4, if the number formed by the last two digits is divisible by 4 For example: 824 is divisible by 4… because 24 is divisible by 4 24÷4=6

8. A number is divisible by 5, if the number ends in a 0 or 5 For example: 120 and 325 are both divisible by 5 120 ends in 0 325 ends in 5

9. A number is divisible by 6, if the number is divisible by 2 and 3 For example: 36 is divisible by 2 since 6 is even 36 is divisible by 3 since 3+6=9 and 9 is divisible by 3 So, 36 is divisible by 6!

10. A number is divisible by 7, if you can take the last digit, double it and subtract it from the remaining number and the answer is divisible by 7 For example: 203 is divisible by 7… because 3 doubled is 6, and 20-6=14 14 is divisible by 7 14÷7=2

11. A number is divisible by 8, if the last three digits are divisible by 8 For example: 1280 is divisible by 8… because 280 is divisible by 8 280÷8=34 so, 1280÷8=160

12. A number is divisible by 9, if the sum of the digits is divisible by 9 For example: 7056 is divisible by 9… because 7+0+5+6=18 and 18 is divisible by 9 18÷9=2

13. A number is divisible by 10, if the last digit is a zero For example: 100, 240, 3750, 48,720 are all divisible by 10

14. If you memorize the divisibility rules, math will become easier!

15. 2 if the ones digit is divisible by 2 3 if the sum of the digits is divisible by 3 4 if the # formed by the last two digits is divisible by 4 5 if the last digit is a 0 or 5 6 if the # is divisible by 2 and 3 9 if the sum of the digits is divisible by 9 10 if the last digit is a 0