A total of 44 times.
300 times.
As a digit in other numbers it appears 20 times
Infinitely many.
Zero. Only the digits 5 and 0 appear in 500.
A total of 44 times.
200
200
16
19 times.
11 times
11 times
300 times.
300
As a digit in other numbers it appears 20 times
10 times for the one's digit, 1-100 10 times for the ten's digit, 60-70 = 20 times
Infinitely many.