- #1

- 248

- 0

^{m}- 2

^{n}= 63 in which m and n are nonnegative integers.

2. What is the units digit of 6

^{25}- 3

^{24}?

3. How many perfect squares divide the number 4!*5!*6! ?

4. What is the last digit of the sum 1! + 2! + 3! + ... + 2010! + 2011! ?

Thanks!