## Puzzle 91: How many 1's?

If you write out the numbers from 1 to 500, how many times will you write the number 1? Explain your strategy.

Extension: What about if you write out from 1 to 1000? How many 1's? Explain your strategy.

Extension: What about if you write out from 1 to 1000? How many 1's? Explain your strategy.