Is the following conditional true?
if an integer is divisible by 9, then its digits add up to 9.
yes
no

Yes, it is true. Ex. 3 x 9 = 27, 2 + 7 = 9.

If you happen to have a larger number say, 639, you might have to add the digits together multiple times before you have your answer so, 6 + 3 + 9 = 18, then 1 + 8 = 9, so it is divisible by 9.