Question

Smallest three digit number which is divisible by 3 is .
Largest three digit number which is divisible by 3 is .

Answer 1

We know that a number whose sum of digits is divisible by 3 is also divisible by 3.

Smallest 3 digit number is 100, but 100 is not divisible by 3.
We need to check for its consecutively greater number i.e. 101, then 102.

We find that 102 is divisible by 3 because its sum of digits $(1+0+2=3)$ is divisible by 3.


Similiarly, Largest 3 digit number is 999.

999 is divisible by 3 because its sum of digits $(9+9+9=27)$ is divisible by 3.