There are certain things you can try to determine whether a large number is divisible by numbers 2 through 9. There are some shortcuts to help you when you're trying to tackle a problem where you're dividing a large number.
To determine the divisibility of a number, you can follow these steps:
1. If a number is divisible by 2 the last digit will be 0,2,4,6,or 8.
2 If a number is divisible by 3, the sum of its digits is divisible by 3. Just add the digits in the number, for instance, 432. 4+3+2=9 - therefore, you know that the number 432 is divisible by 9.
3. A number is divisible by 4 if the number that totals the last two digits is divisible by 4. For example, in the number 724 the number 24 is divisible by 4.
4. A number is divisible by 5 if the last digit is 0 or 5.
5. A number is divisible by 6 if it is divisible by 2 AND 3.
6. A number is divisible by 7 if you follow these examples from
Basic-Mathematics.com:
Is 348 divisible by 7? Remove the last digit, which is 8. The number becomes 34. Then, Double 8 to get 16 and subtract 16 from 34. 34 − 16 = 18 and 18 is not divisible by 7. Therefore, 348 is not divisible by 7.
Is 37961 divisible by 7? Remove the last digit, which is 1. The number becomes 3796. Then, Double 1 to get 2 and subtract 2 from 3796. 3796 − 2 = 3794, so still too big? Thus repeat the process. Remove the last digit, which is 4. The number becomes 379. Then, Double 4 to get 8 and subtract 8 from 379. 379 − 8 = 371, so still too big? Thus repeat the process. Remove the last digit, which is 1. The number becomes 37. Then, Double 1 to get 2 and subtract 2 from 37.37 − 2 = 35 and 35 is divisible by 7. Therefore, 37961 is divisible by 7.
7. A number is divisible by 8 if the number that is represented by its last three digits is divisible by 8.
8: A number is divisible by 9 if the sum of its digits is divisible by 9.
9. A number is divisible by 10 if the last digit is zero.