One of the trickiest jobs at a zoo is feeding the sharks. Ripley Aquarium in Toronto, Canada gives a great behind-the-scenes peek here at mealtime in their “Dangerous Lagoon.” First the zoo workers, or “aquarists,” have to scoot the sea turtles out of the tank. Each turtle has been trained to see and swim towards its own colored stick (who knew turtles were that smart?). Then the fish who like to eat at the top of the water are fed; the workers drop the food into the corners of the tank, so the hungry fish swim there. For fish who eat along the bottom, their food is shot down there through tubes. Finally, with everyone else out of the way, the aquarists stick fish on a long pole and hold it out over each shark’s special spot in the water. The sharks eat just 3 times a week, but together they chow down 1,000 pounds of fish in that time!
Wee ones: If the sharks eat 3 times in a week and have eaten twice already, how many more meals do they have left?
Little kids: If the sharks eat every other day starting on Monday (meaning they eat, then skip a day, then eat…), on what days do they eat their other 2 meals? Bonus: If the sharks eat 3 times in a week, how many days do they not eat?
Big kids: If the sharks are fed 300 pounds on each of their days, do they get their full 1,000 pounds of fish? Bonus: If there are 5 sharks in the tank and they all eat the same amount, how much food is each one eating in a week?
Answers:
Wee ones: 1 more time.
Little kids: Wednesday and Friday. Bonus: 4 days.
Big kids: No, since that will add up to “only” 900 pounds. Bonus: 200 pounds per shark.

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.