Ninja were secret warriors hundreds of years ago who could leap, run and climb super-fast and super-quietly. Well, one girl decided she wanted to practice being a ninja, so her very cool dad built a training course in their backyard. She has to jump through a set of slanted boards, balance on wobbly, seesawing beams, and dash over the roofs of not one but two sheds. If you could do it, you might be a ninja, too!
Wee ones: If you leap onto a slanted step facing left, then another facing right, then another facing left, then facing right…which way does the next one face?
Little kids: If you’re 10 seconds from finishing the ninja course, what numbers do you say to count down? Bonus: If there were 9 slanted steps for her to zigzag through, starting facing left, then right, then left and so on, how many slants would face each way?
Big kids: If the whole thing takes 2 1/2 minutes, how many seconds does it show on the stopwatch when she’s done? Bonus: If the sheds took a whole 1/3 of that time, how many seconds would they take? (Hint if needed: What if they took just 1/3 of 15 seconds?)
Answers:
Wee ones: It faces left.
Little kids: 10, 9, 8, 7, 6, 5, 4, 3 ,2, 1. Bonus: 5 would face left, and 4 would face right.
Big kids: 150 seconds. Bonus: 50 seconds.
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.