Question

How many numbers are there between 100 and 1000 if numbers are only 2 and 9

Answer 1

Step-by-step explanation:

Just think in your mind that you have 3 boxes one for unit place one for tens place and one for hundred place. As we want the number between 100 and 1000 all are 3 digit no. except 1000 and we know it can be neglected.

so for unit place we have two choices either 2 or 9. same for tens place and hundred place. so the answer is 2×2×2=8.