1a. Evaluate the mean value of (m!-n!)mod(10)
1b. Evaluate the mean value of (m!-n!)mod(3)

Let m and n be two digit integers (10 to 99) with m>n

2a. Evaluate the mean value of (m!-n!)mod(10)
2b. Evaluate the mean value of (m!-n!)mod(3)

3. Find recursive formulas for n digit integers.