It’s hard to tell whether these hippos are playing, kissing, or just shoving each other out of the way. Hippo is short for “hippopotamus,” which means “river horse.” Hippos are the 3rd largest land mammal, after the elephant and the white rhinoceros, but their closest cousins are another set of chubby mammals: whales and dolphins! Well, hippos love water just like they do, and it looks like they love to play, too.
Wee ones: Hippos have 4 short, stumpy legs. What numbers would you say to count them?
Little kids: Hippos need to breathe every 3 minutes. If a hippo swims for 3 minutes, comes up for 1 minute, then goes under for 3, how many minutes does that take? Bonus: If it keeps up that pattern, is the hippo swimming or breathing at 10 minutes?
Big kids: If you ride on your 3,300-pound pet hippo, how much do you weigh together? Find out your weight in pounds! Bonus: If a rhino weighs 4,000 pounds, a horse weighs 1,000 pounds, and a hippo’s weight is halfway between, how much does the hippo weigh?
The sky’s the limit: A hippo can live for 45 years. If a hippo’s grandkids are all ages that divide neatly into 45, with 1 hippo of each age, at least how many grandkids must it have?
Wee ones: 1, 2, 3, 4.
Little kids: 7 minutes. Bonus: Swimming, until 11 minutes are up.
Big kids: Different for everyone…add your weight to 3,300. Bonus: 2,500 pounds.
The sky’s the limit: Five hippo grandkids: 1, 3, 5, 9, and 15.
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.