If I write down all the numbers from 1 to 100, then how many times I have written the digit 3?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 20
The digit 3 is counted place by place, units and tens separately, so that a number such as 33, which has the digit twice, is counted twice.
3 in the units place: 3, 13, 23, ..., 93, that is, 10 times
3 in the tens place: 30, 31, ..., 39, that is, 10 times
Total: \(10+10=20\) (100 has no 3)