13. Even choosing a huge number like, [893,752,075,983] it will not work, because the last digit is a 3.
14. Divisibility by 6 If the number is divisible by 2 and 3, then it is divisible by 6.
15. Example: looking at the number 1536, using the rules for both 2 and 3 we see that it checks in both: 2: if the last digit is an even number √ yes 3: add 1+5+3+6=15 √ yes
16. Now taking a number like 1537, we already know that it will not work because the last digit is not an even number. We have to check both rules for 2 and three because sometimes one will check and the other will not & if one rules fails, you will automatically know that it isn’t going to work. If one rule doesn’t work…
17. Divisibility by 8 If the last three numbers are divisible by 8, then the original number is divisible by 8.
18. Example: 1328 8/328= 41 so this number is divisible by 8. If the number would have had a remainder then the number would not work.
19. If the sum of the digits is divisible by 9, then the number is divisible by 9. Divisibility by 9
20. Example: 216, 2+1+6=9. 217 would not work because 2+1+7=10 and 10 is not divisible by 9.
21. Pay close attention, this rule is tricky! Find the sum of the odd numbered digits, and subtract that number from the sum of the even number digits. Divisibility by 11
23. If the number is divisible by 3 and 4, then it is divisible by 12. Divisibility by 12
24. Example: 3156 3: 3+1+5+6= 15 which is divisible by 3… check 4: last two digits are divisible by 4 This number is divisible by 12.
25. Now that you have learned some great rules for divisibility, it will make it easier and help take up less time when figuring out if it is divisible by certain numbers. Ending!
