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Common Core Standard:  4.OA.4   4th Grade Math

 The divisibility rules for 2 are simple. If the last digit of the number is even it is divisible by 2.    So if the number ends in a 0, 2,4,6,8 it is divisible by 2. Number Divisible Why? 66 yes Ends in 6 which is an even number 203 No 3 is not divisible by 2 48 yes Ends in 8 which is divisible by 2

### Divisibility Rules for 2, 3. 4,and 5

 In order for a number to be divisible by 6 the number must be an even number and,   If you add the digits together this number must be divisible by 3 Number Divisible by 6? Why 72 Yes 72 is an even number and 7+2=9 is divisible by 3 357 No The number is not even. 138 Yes The number is even and 1+3+8 =12 is divisible by 3 In order for a number to be divisible by 8 look at the last three digits and if this number is divisible by 8 then the entire number is divisible by 8 Number Divisible by 8? Why 3648 Yes 648/8 = 81 so the number formed by the last three digits is divisible by 8 5679 No 679 is not divisible by 8 so the entire number is not divisible by 8 In order for a number to be divisible by 9 simply add the digits together and if this number is divisible by 3 and 9 then the entire number is divisible by 9 Number Divisible by 9? Why 234 Yes 2+3+4 = 9 which is divisible by 3 and 9 897 No 8+9+7 = 24 which is not divisible 9 561 Yes 5+6+1 = 12 which is divisible by 3 and 9 In order to be divisible by 10 the number must end in 0 Number Divisible by 10 Why 220 Yes Ends in 0 678 No Does not end in 0 43780 Yes Ends in 0 In order for a number to be divisible by 12 it must divisible by 3 and 4 Number Divisible by 12? Why 1044 Yes Is the number divisible by  3 ? 1+4+4=9 which is divisible by 3 and the last two digits 44 is divisible by 4 204 Yes 4+2 =6 which is divisible by 3 and the last two digits 04 is divisible by 4 878 No The sum of the numbers 8+7+8 = 23 is not divisible by 3

 If the last digit ends in 0 or 5 then it is divisible by 5​ Number Divisible by 5 ? Why 55 Yes 55/5 =11 Ends in 5 456 No 456/5 = 91.2 Ends in 6 650 yes 650/5 = 130 Ends in 0

 You  have two choices 1. If you combine the last two digits together is their sum divisible by 4? If so, the entire number is divisible by 4 2. Divide the number by 2, and if the sum is even then the number is divisible by four. ​ Number Divisible by 4 ? Why 56 Yes 56/2 = 28 and it is even 786 No 786/2 = 393 which is odd or 86  is not divisible by 4 128 yes 128/2 = 64 which is even         or  28 is divisible by 4

# Divisibility Rules Chart

Use this divisibility rules chart to help determine if one number is divisible by another.

 The divisibility rules for 3 require one to add the  numbers together and see if the  product is divisible by three Number Divisible by 3 ? Why 39 yes 9+3 = 12 which is divisible by 3 and passes the divisibility rules 162 yes 1+ 6+2 = 9 which is divisible by 3 67 no 6 + 7 = 15 which is not divisible by 3 therefore does not follow the divisibility rules