Question

1. I am a number between 120 to 130 and I am divisible by 3, 6 and 9. Who am I?​

Answer 1

126

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.

Answer 2

the answer is 126
126/3=42
126/6=21
126/9=14