Answer:
126
Step-by-step explanation:
A number is divisible by 3 if its sum of digits is divisible by 3 (you can do it over and over again until it's one digit!).
A number is divisible by 2 if its last digit is 0, 2, 4, 6 or 8.
A number is divisible by 6 if it is divisible by 2 and by 3.
A number is divisible by 9 if its sum of digits is divisible by 9 (you can do it over and over again until it's one digit!).
So we need a number with last digit 0, 2, 4, 6, or 8 (because it's divisible by 6 hence by 2) and with a sum of digits divisible by 9 (because if it's divisible by 9 it's also divisible by 3).
130 is not divisible by 9, so the first digits must be 12X.
to get a number divisible by 9, we need to add a digit D so that 1+2+D is divisible by 9.
9 - 1 - 2 = 6
126 is divisible by 9 because it's sum of digits is 9. It's also divisible by 6, because it is divisible by 3 and its last digit is 6.
