Between staying up late during vacation, and New Year’s Eve coming up this week, lots of sleepy people will be yawning more than usual. They’ll open their mouths wide and not be able to talk right while yawning, which on average takes 6 seconds. Some scientists think that yawning gives us energy, by putting more oxygen into our blood. We also seem to yawn when we’re bored. But the weirdest thing is that yawning people make other people yawn. Really, next time you’re in a group, try yawning: there’s more than half a chance that someone else will yawn within 5 minutes! Apparently you can even get your dog to yawn by yawning in front of him…of course, if your pet pooch stayed up late for New Year’s, maybe he’s just tired, too.

*Wee ones:* What numbers would you say (in your head!) to count off your 6-second yawn?

*Little kids:* If you yawn 7 times and your friend yawns just 2 times, how many more times did you yawn? *Bonus:* If you yawn 5 times a day, how many times do you yawn in a week? See if you can count up by 5s!

*Big kids:* If your yawn makes 2 other kids yawn, and each of them makes 2 more kids yawn, and each of them makes another 2 more kids yawn, how many of you have yawned in total? *Bonus:* At least how many more rounds like that would you need to have 50 people all yawn at least once?

*The sky’s the limit:* If there are 30 yawns in a room, and 4 times as many yawns come from dogs as people, how many of each just yawned?

Answers:

*Wee ones:* 1, 2, 3, 4, 5, 6.

*Little kids:* 5 more times. *Bonus:* 35 times: 5, 10, 15, 20, 25, 30, 35.

*Big kids:* 15 kids, including you (1+2+4+8). *Bonus:* 2 more rounds. The next round will add 16, giving us just 31, so you’ll need that next round of 32 possible yawns to reach 50.

*The sky’s the limit:* 6 people and 24 dogs. If there are 4 dogs for each yawning person, the yawners come in sets of 5, and 30 would have 6 of those sets. If you want to show with algebra, for p people and d dogs we have:

p + d = 30

d = 4p

Substituting into the 1st equation, we get

p + 4p = 30

5p = 30

p = 6 = number of people, so that gives us 4 x 6 = 24 dogs.

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.