Figure This!

Four challenges will tempt your clever brain: figure out the time you have to wait in line; which shape will hold the most popcorn; when you would have the billionth beat of your heart, given a starting time; or why manhole covers aren't square... Ready? For even more printable challenges this summer, download 80 challenges at the 2nd link below and create your own challenge workbook.

http://www.figurethis.org/challenges/toc.htm

http://www.figurethis.org/challenges/challenge_index.htm