This Week From Bedtime Math: Messed-up Pennies

A penny can&t really buy much these days…unless it was made the wrong way. Count up some valuable mistakes in today&s challenge from Bedtime Math!
By Laura Overdeck
Jan 21, 2014



This Week From Bedtime Math: Messed-up Pennies

Jan 21, 2014

What is Bedtime Math? A message from Laura: Bedtime Math is a pretty simple idea: We all know we should read to our kids at night, but what about math? My husband and I have done fun, mischief-loaded math problems with our kids at night for years, and when at age 2 our third child started hollering for his own math problem, we realized we were onto something:  In a world where so many people say, "Ewww, math!" we had created a household culture where kids don't just tolerate math, they actually seek it out. Now, every week, we'll be posting a new problem right here on Scholastic Parents!
When people tell others what they think, they might say, "That's my two cents." We also offer people "a penny for your thoughts." I guess we think our own thoughts are worth more than other people's. Well, maybe both numbers are right: a penny, which is worth 1 cent, costs 2 cents to make! The American government has tried to deal with this problem, like in 1943 when they made steel pennies to save on copper…and it was a disaster. Unlike any other coin, the steel pennies were magnetic, so coin machines that stopped fake magnetic coins also stopped the steel ones. They also got mixed up with dimes since they were silver-colored. Meanwhile, some odd pennies are worth a lot just because there are fewer of them, as we'll discuss below. Unfortunately, a vending machine won't know the difference, so don't spend them there!

Wee ones: If you have 3 regular copper pennies and 1 of these special 1943 steel pennies, 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 penny), how many real dimes do you have?  Bonus: Given that dimes are worth 10 cents each but a penny is worth just 1 cent, how much money do you have in that pile?

Big kids: Another special set of pennies comes from 1955. Coins are stamped twice to press the picture harder, but these pennies shifted after the first hit so they ended up with the design showing double. Only 24,000 messed-up pennies like this were made. What is the face value of all these 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 could you make from selling them?
Wee ones: 4 pennies total.
Little kids: 5 dimes.  Bonus: 52 cents. The dimes are worth 50 cents, and the pennies add 2 cents.
Big kids: $240.  Bonus: $3,000 total.

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