Question

I think a number of divide it by 7
add 10. The result is 14. ​

Answer 1

Answer:

Take the last digit in a number.

Double and subtract the last digit in your number from the rest of the digits.

Repeat the process for larger numbers.

Example: Take 357. Double the 7 to get 14. Subtract 14 from 35 to get 21, which is divisible by 7, and we can now say that 357 is divisible by 7.