Every day, Bedtime Math posts a fun, new math problem for parents to do with their kids.  Check us out at www.bedtimemath.org!  Here's a sample problem ~

When you mail a letter, you need to stick a stamp on it, which is how we pay for mail to get from one place to another.  And you can't just slap it on any which way like a SpongeBob sticker.  The stamp has to go in the top right corner, it has to be right side up, its squiggly edges can't overlap the squiggly edges of the stamp next to it - it's serious business.  But that isn't how stamps always worked.  Before the year 1800, in most places the person getting the letter was expected to pay the postage.  Eventually people started pre-paying with stamps, but even then they could pay just part of it, and stick the person at the other end with paying the rest.  If only we could stick our monthly texting plan on someone else...

Wee ones (counting on fingers): American stamps can have all kinds of pictures on them.  If you have 2 endangered-species stamps, 2 plain old flag stamps, and 1 of the new Aloha shirt stamps, how many stamps do you have?

Little kids: Another crazy thing is that back in the 1800's, you could tear a stamp in half and use each piece separately for half the value.  If you had a 40-cent stamp and tore it in half, how much would each half count for?  Bonus: As you see here, those Hawaiian-shirt stamps cost only 32 cents.  If you tore one of those in half, now how much postage does a half count for?

Big kids: The very first U.S. stamp ever printed cost just 3 cents.  Today, a stamp for a first-class letter costs 45 cents!  How many of those 3-cent stamps would you need to mail a letter today?    Bonus: The 3-cent stamp appeared in 1842.  For how many years have we been using stamps to send mail?

Answers:

Wee ones: 5 stamps.

Little kids: 20 cents.  Bonus: Just 16 cents.

Big kids: 15 stamps.  Bonus: 170 years.