The easiest way to do this is to break this into cases:
Case 1: Number Starts with 2 (20-29).
20, 21, 22, 23, 24, 25, 26, 27, 28, 29
n = 11 (it's 11, because 22 has the number twice)
Case 2: Number ends with 2 (12, 32, 42... )
12, 32, 42, 52, 62, 72, 82, 92
n = 8 (we skipped 22, because we counted it in case 1)
11 + 8 = 19
2 appears 19 times from 10 to 100
As a digit in other numbers it appears 20 times
Infinitely many.
18
20000 times
18 times
11 times
As a digit in other numbers it appears 20 times
Infinitely many.
18
20000 times
A total of 44 times.
18 times
200
200
16
700000
It appears 25 times.