How many integers are there between $100$ and $1000$ all of whose digits are even?

1. $60$
2. $80$
3. $100$
4. $90$

_ _ _

1. In the units place the possible number can be vary from 0,2,4,6,8
2. In the tens place similarly, outcome is the same as number can vary from 0 to 8
3. But the story is not the same in case of hundredth place as number should be greater than 100 thus the only possible outcome is 2,4,6,8
4.  So 4*5*5 = 100 possibilities are there in which all the digits can be even.
480 points