What happens when you add 4 pools + 300 dogs? You get a big, hairy, splashy party. Every year the town pool in Calgary, Canada has Dog Day. The pools need cleaned at the end of summer, so why not let dogs splash around in there first? Best of all, dog owners pay to let their doggies paddle, and the money collected helps take care of rescued animals. By the way, grown-ups and kids can swim with the pooches, too, if you don’t care whether the water is clean…
Wee ones: What numbers would you say to count your doggie’s 4 paws?
Little kids: If you and your dog both swim, how many legs do you put in the pool together? Bonus: If they hold the party on a Sunday, and it takes 3 days from then to clean up the mess, on what day are the pools clean again?
Big kids: If a family pays $24 total to bring their 6 dogs into the pool, and each dog costs $3, how much extra did the people pay to swim themselves? Bonus: If the 300 dogs split up evenly among the 4 pools, how many pooches are in each pool?
The sky’s the limit: If there are 50 legs in the pool and there are twice as many dogs as people, how many swimmers of each type are in the pool?
Wee ones: 1, 2, 3, 4.
Little kids: 6 legs. Bonus: On Wednesday.
Big kids: Another $6, because the dogs cost $18. Bonus: 75 dogs per pool.
The sky’s the limit: 10 dogs and 5 people. The dogs and people fall into “sets ” of 2 dogs plus a person, who together have 10 legs. So if there are 50 legs total, there are 5 of these “sets,” giving us 5 x 2 = 10 dogs, and 5 people.
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.