# Just Like Two Peas in a…Mattress

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

# Just Like Two Peas in a…Mattress

November 16, 2015

If you’ve heard the fairy tale of the princess and the pea, you know it’s about a very picky princess. She can feel a tiny pea under her bed, even though it’s under a stack of 20 mattresses and 20 poofy blankets. That’s how the prince knew she was a real princess. But what Bedtime Math fan Tanisha T. wants to know is, how many peas could we stuff into a whole mattress? We think the peas are used to being squashed, since they grow all jammed together inside a long, skinny green pod. They’re also really good for you: a serving of peas has more vitamin C than 2 apples. None of this sounds like good stuffing for a bed, by the way. But now that we know we can fit 3 peas per inch (see photo), let’s find out how many can fit under that prickly princess.

Wee ones: What shape is a pea?

Little kids: If you can fit 3 peas in a row, and then make 3 rows to fill a square inch, how many peas fit in that square?  Bonus: If they came from just 2 pods, and each pod had at least 2 peas, how many ways could they have been split between the pods? (Don’t worry about the order of pods.)

Big kids: A cube that’s 1 inch wide in every direction can fit 3 layers of those 9-pea squares. How many peas fit in a cubic inch?  Bonus: They say that British people eat 9,000 peas per year on average. If you ate 20 per day, would you be keeping up? (Hints if needed: A year has 365 days…and multiplying by 20 is like multiplying by 2 and then by 10.)

The sky’s the limit: If there are 3x3x3 peas in a cubic inch, and a mattress is 200 inches long, 50 inches wide, and 10 inches thick, how many peas can we fit after all?