Backyard Ninja

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

Backyard Ninja

October 12, 2018

Have you ever wanted to be a ninja? Ninja were secret warriors in Japan hundreds of years ago (and maybe even today — it’s a secret). A ninja has to leap, run and climb super-fast and super-quietly. Well, one girl decided she wanted to practice to become a ninja. So her very cool dad built her a giant ninja training course in their backyard. As this video shows, 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. She finishes the course in about 2 1/2 minutes. Do you think you could do it faster? If yes, 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?)










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.

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About the Author

Laura Overdeck

Laura Overdeck

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.

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