10 Super Fun Math Riddles for Kids! (with Answers) There is also a link to download a Free Printable PDF Math Riddles Worksheet and Answer Key that shares all of these riddles at the end of this post!. All of the math riddles, puzzles, and brain teasers below are from the best-selling 101 Math Riddles, Puzzles, and Kids Ages 10+! PDF workbook, which is now available!