Divisible by 9?

Question

Give me some tips and tricks when doing divisiblity (9)

Answer 1

When the sum of the digits of a number is divisible by 9,then the number itself is divisible by 9.
for example take a number say 1782.the sum of the digits of the number is 1+7+8+2=18.As 18 is exactly divisible by 9, the number 1782 is also exactlydivisible by 9.

Answer 2

a good one for 9s is to put up your 10 fingers in a row, your right hand being numbers 1-5 and your left 6-10. then, just put down the finger you are multiplying by. if you are doing 6x9, put down the first finger in your left hand. you will have five fingers, the blank and then 4 fingers, so the answer is 54.

have yourself a good day.