# Putting the “Sleep” in “Sleepover”

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.

# Putting the “Sleep” in “Sleepover”

September 26, 2014

If you’ve ever slept over at a friend’s house, you know how hard it is to sleep at these things. It’s just too much fun to be with people you don’t normally see at that time. You find out what they eat for dinner, what cartoon character they wear on their PJs, and what stuffed animals get the most important spots on their bed. The problem is that even though you’ll fall asleep really late, you might wake up early the next morning anyway, since you’re used to it. That’s called your diurnal rhythm, your 24-hour pattern of doing activities like waking up or eating meals. But your circadian rhythm is one you can’t control as easily: it’s your body’s own clock, and it wants to take about 24.2 hours per day instead of 24. So even when we don’t have sleepovers, our bodies wish they could sleep a little longer. The lesson from all this: at any age we can all use a good nap.

Wee ones: If your friend invites you and 3 other friends to a sleepover, how many of you are there in total?

Little kids: If you normally wake up at 7:00 am, but at the sleepover you manage to sleep 1 hour later than that, when do you wake up?  Bonus: If everyone finally fell asleep at 11:00 pm and you all wake up at 6:00 am, how many hours of sleep do you get?

Big kids: If 3 people each bring 4 stuffed animals to the sleepover and the other 3 people each bring 6, how many stuffed animals have to squeeze in with everyone?  Bonus: If everyone’s sleeping bag is 3 feet wide and 6 feet long, and the room is 12 feet by 12 feet, how many sleeping bags can fit side by side and end to end if you take out all the furniture to make space?

Answers:
Wee ones: 5 people — remember to count yourself!

Little kids: At 8:00 am.  Bonus: 7 hours.

Big kids: 30 stuffed animals.  Bonus: 8 sleeping bags: you can fit 4 across (3+3+3+3) and 2 deep (6+6).

And thank you Isabel L. for this very mathematical, not-so-sleepy topic!

### Laura Overdeck

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.