A printer is typesetting a book. He needs one piece of type for each digit in the page numbers of the book. Each piece of type can be used only once. For example, page 3 and page 33 will require 3 pieces of type. How many twos will he need to number pages 1 through 232?

Question

***[isuru]*** · Answer

2's in the ones place: 2, 12, 22, 32, ... 232 = 24 
2's in the tens place: 20 - 29, 120-129, 220-229 = 30 
2's in the hundreds place: 200 - 232 = 33 

so 24 + 30 + 33