Cookies for Your Pet Grasshopper

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.

Cookies for Your Pet Grasshopper

October 28, 2018

We know that bugs like to eat our people food: just go on a picnic and watch the ants sneak up on you. So our fan Joey K. asked a great question: how fast could a grasshopper eat a cookie? Well, if grasshoppers like cookies as much as ants do, we can figure this out! Scientists aren’t sure how fast a grasshopper eats, but they do know that it can eat 16 times its own weight in 1 day, which is crazy. These bugs each weigh about half a gram, so the grasshopper could eat only 8 grams of cookie…to compare, 2 teaspoons of water weigh about 10 grams. Cookies come in all sizes, but if we go with the average of 16 grams, the bug would take 2 whole days to finish it off. We humans snarf them down a lot faster!

Wee ones: Most cookies are circles. Try to spot 4 circles in your room.

Little kids: If the grasshopper has taken 4 bites of cookie, what numbers are the next 3 bites? Bonus: If the grasshopper counts down the 8 grams of cookie while eating, what numbers does she say starting with 8?

Big kids: If the grasshopper starts eating 4 average cookies on a Monday, what’s the soonest day he can finish eating them? (Reminder: the grasshopper takes 2 days to eat 1 average cookie.) Bonus: If a giant grasshopper can eat 50 grams of cookie in a day, on what number cookie is his last bite?  (They’re all 16-gram cookies.)

The sky’s the limit: If a grasshopper eats 1/4 of a cookie, then the next day she eats 1/3 of what’s left, then on the 3rd day she eats 1/2 of what’s still left, what fraction of the total cookie is still there?

 

 

 

 

 

 

 

 

Answers:
Wee ones: Items might include a clock face, a plate, the edge of a cup, a button, or the flat end of a crayon.

Little kids: Bites 5, 6 and 7. Bonus: 8, 7, 6, 5, 4, 3, 2, 1!

Big kids: On the Tuesday a week later, since it takes 8 days. He’ll finish cookies on Weds, Fri and Sun.  Bonus: The 4th cookie, since 3 cookies will weigh 3 x 16 = 48 grams.

The sky’s the limit: 1/4 of the starting cookie. When the grasshopper eats 1/4 of the cookie, 3/4 are left. When she eats 1/3 of that, that’s like leaving 2/3 of it behind. And just as you multiply by 2 if you want 2 of them, you multiply by 2/3 if you want just 2/3 of it. So we do 3/4 x 2/3 = 1/2. The last day she eats 1/2 of what’s left, which is like leaving 1/2. So again we multiply: 1/2 x 1/2 = 1/4 left.

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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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