Multiple choice general knowledge math & puzzles

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

  1. 10

  2. 11

  3. 19

  4. 20

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The digit 9 appears in the units place 10 times (9, 19, 29... 99) and in the tens place 10 times (90, 91, 92... 99). The number 99 is counted in both, totaling 20 instances of the digit 9.