How many times will the digit 3 be written when listing the integers from 1 to 1000?

How many times will the digit 3 be written when listing the integers from 1 to 1000?

Quiz

Answer/Solution

300

Steps/Work

Many approaches are possible. For example:
Consider numbers from 0 to 999 written as follows:
1. 000
2. 001
3. 002
4. 003
...
...
...
1000. 999
We have 1000 numbers. We used 3 digits per number, hence used total of 3*1000=3000 digits. Now, why should ANY digit have preferences over another? We used each of 10 digits equal # of times, thus we used each digit (including 3) 3000/10=300 times.
Answer: C.