A penny is worth just 1 cent, and worse yet, it costs nearly 2 cents to make one! But some pennies are worth a lot because the machines made the first few pennies wrong, with crooked letters or the wrong mix of metal. Once they fix the problem, there are just those few messed-up pennies, and suddenly those coins are special. As you see from this list, you can sell them for hundreds or even thousands of dollars!
Wee ones: If you have 3 regular copper pennies and 1 special 1943 steel penny, how many do you have altogether?
Little kids: If you have what looks like 7 dimes, but a magnet picks up 2 of them (which means it’s a 1943 steel penny), how many real dimes do you have? Bonus: Dimes are worth 10 cents each. What are the 5 real dimes worth?
Big kids: On some 1955 pennies, the design shows double – but only on 24,000 of them. What is the face value of all those pennies in dollars? (Reminder: there are 100 pennies in a dollar.) Bonus: Because they’re so rare, collectors will pay up to $1,500 for just one of these pennies. If you have 2 of them, how much money would you get for them?
Answers:
Wee ones: 4 pennies total.
Little kids: 5 dimes. Bonus: 50 cents.
Big kids: $240 dollars. Bonus: $3,000 total.

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.