[Testing] Test Number Divisibility

Pay attention on Number 3, 7, 9 and 11.

Divisible by:	If:	Examples:
2	The last digit is even (0,2,4,6,8)	128 is 129 is not
3	The sum of the digits is divisible by 3	381 (3+8+1=12, and 12÷3 = 4) Yes 217 (2+1+7=10, and 10÷3 = 3 ¹/₃) No
4	The last 2 digits are divisible by 4	1312 is (12÷4=3) 7019 is not
5	The last digit is 0 or 5	175 is 809 is not
6	The number is divisible by both 2 and 3	114 (it is even, and 1+1+4=6 and 6÷3 = 2) Yes 308 (it is even, but 3+0+8=11 and 11÷3 = 3 ²/₃) No
7	If you double the last digit and subtract it from the rest of the number and the answer is: 0, or divisible by 7 (Note: you can apply this rule to that answer again if you want)	672 (Double 2 is 4, 67-4=63, and 63÷7=9) Yes 905 (Double 5 is 10, 90-10=80, and 80÷7=11 ³/₇) No
8	The last three digits are divisible by 8	109816 (816÷8=102) Yes 216302 (302÷8=37 ³/₄) No
9	The sum of the digits is divisible by 9 (Note: you can apply this rule to that answer again if you want)	1629 (1+6+2+9=18, and again, 1+8=9) Yes 2013 (2+0+1+3=6) No
10	The number ends in 0	220 is 221 is not
11	If you sum every second digit and then subtract all other digits and the answer is: 0, or divisible by 11	1364 ((3+4) - (1+6) = 0) Yes 3729 ((7+9) - (3+2) = 11) Yes 25176 ((5+7) - (2+1+6) = 3) No
12	The number is divisible by both 3 and 4	648 (By 3? 6+4+8=18 and 18÷3=6 Yes. By 4? 48÷4=12 Yes) Yes 524 (By 3? 5+2+4=11, 11÷3= 3 ²/₃ No. Don't need to check by 4.) No

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