How many times does the digit '3' appear in numbers from 1 to 100?
Answer: C
Let's count the occurrences of the digit '3'.
In the units place: 3, 13, 23, 33, 43, 53, 63, 73, 83, 93 (10 times).
In the tens place: 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 (10 times).
The number 33 is counted in both lists. So the total count is 10 + 10 = 20.