The post The Teeniest Toothpick Building appeared first on Bedtime Math.

]]>For a long time, the Empire State Building was the tallest building in all of New York City. But this tiny wooden one holds the world record in the other direction. Steven Backman made this super-small Empire State Building sculpture out of pieces of toothpicks, using regular old tools like a razor blade, pliers, and glue. This teeny building is less than 1 inch tall and is “to scale,” meaning its height, length and width relate in the same way as for the real building…if the building is 200 times as tall as it is wide, so is this one. In the video we see that he’s also made a tiny Big Ben (the famous London clock tower), the Golden Gate Bridge from San Francisco, and other buildings — all from toothpicks. If *you* have toothpicks handy, try making a model of your house or another favorite building…and if you want to go bigger, check out this page on using mini marshmallows to build giant structures fast!

*Wee ones:* How many toothpick sculptures can you count in the photo at the very top?

*Little kids:* If Steven needed 1 toothpick as the center of the building and cut pieces off 5 others, how many toothpicks did he use in total? *Bonus:* If he used another 7 toothpicks to nibble on snacks while working, now how many did he use?

*Big kids:* If Steven’s teeny 4-sided sculpture has 4 ridges glued onto each side, how many little pieces did he glue on? *Bonus:* The real Empire State Building has 6,500 windows. If Steven could fit only 100 tiny windows on his sculpture, how many are missing?

*The sky’s the limit:* The Empire State Building (without the spire) is 1,250 feet tall. If Steven’s sculpture was exactly 1 inch, how many times as tall is the real building? (Reminder if needed: A foot equals 12 inches; and you can break 1250 into 1000, 200 and 50 and multiply each piece by 12 before adding back together).

Answers:

*Wee ones:* 8 toothpick sculptures.

*Little kids:* 6 toothpicks. *Bonus:* 13 toothpicks.

*Big kids:* 16 pieces. *Bonus:* 6,400 fewer windows.

*The sky’s the limit:* 15,000 times as tall! Just multiply 12 inches per foot times 1,250 feet.

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]]>The post Backwards-Brain Bike appeared first on Bedtime Math.

]]>Have you ever ridden a bike? Once you learn how to do it, it seems easy. But imagine trying to ride a backwards bike: when you turn the handlebars left the bike goes to the right, and when you turn them right, the bike curves left. Destin of Smarter Every Day built a bike that does exactly that, and found out that it’s really hard to make your brain work backwards. He practiced every day for 8 months before he could do it, and guess what: he then tried to ride a regular bike and couldn’t do it anymore! He had to relearn. Destin has told people that if they can ride the bike 10 feet on the first try without falling down, he’ll pay them $200…and as we see in the video, no one has done it. The best part is that his 3-year-old son learned to ride it in just 2 weeks. So maybe kids are smarter than grown-ups after all!

*Wee ones:* If you turn left, then right, then left, then right, then left…which way do you turn next?

*Little kids:* If you try to ride the 10 feet to win the $200, but you fall down 2 feet before the end, how far did you ride? *Bonus:* If he took 8 months to make his brain work backwards to ride this thing and it’s now May, when did he start?

*Big kids:* If 3 people ride to the finish without falling down, how much money does Destin have to pay out? *Bonus:* If he doesn’t want to give out more than $1,000 in total, how many bike-riders could he pay at $200 apiece?

Answers:

*Wee ones:* You turn right.

*Little kids:* 8 feet. *Bonus:* In September.

*Big kids:* $600. *Bonus:* 5 riders.

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]]>The post A Toy Copter You Can Ride appeared first on Bedtime Math.

]]>Remote-control helicopters are a ton of fun, as we saw with the world’s smallest quadcopter. But now people are going a step further by *riding* these things. If it’s a big enough copter with big enough propellers, it can carry a person. Then it’s really a hoverboard, meaning a board you stand on that can stay still up in the air. In this video we see inventor Catalin Duru riding an octocopter. He set a world record for the longest hoverboard flight, flying 905 feet across Lake Ouareau in Quebec, Canada. That’s 3 times the length of a football field! He flew it over water because it would be dangerous to fall off the machine from 16 feet high. But maybe someday these hoverboards will be so safe that that’s how we’ll all get around.

*Wee ones:* If you count up the octocopter’s 8 propellers, what numbers do you say?

*Little kids:* How many more propellers does an octocopter have (8) than a quadcopter (4)? *Bonus:*Catalin flew 16 feet above the water. If you climbed up a sailboat’s mast to 13 feet high and you’re 4 feet tall, could you have reached out and touched him?

*Big kids:* Catalin actually made the record-breaking ride last August! How many months ago was that? (Right now we’re in May.) *Bonus:* If Catalin flew for 31 seconds on the water, then fell off and swam for 15 seconds, how long did the whole adventure last?

*The sky’s the limit:* If Catalin flew that 905 feet and 2 inches as a round trip — 1/2 of it to the middle of the lake, then the other 1/2 coming back — what’s the farthest he could have flown out over the lake? How do you split a number like that in 1/2?

Answers:

*Wee ones:* 1, 2, 3, 4, 5, 6, 7, 8.

*Little kids:* 4 more propellers. *Bonus:* Yes, because you’d reach 17 feet.

*Big kids:* 9 months ago. *Bonus:* 46 seconds.

*The sky’s the limit:* 452 feet 7 inches, if he stopped and turned right around. You can break this down into pieces: half of 900 is 450; then 1/2 of the remaining 5 feet is 2 1/2 feet, or 2 feet 6 inches; and finally we add on 1/2 of the remaining 2 inches, which gives us 1 more inch.

And thank you John O. for sending us this great story!

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]]>The post Good Luck Wishes – from an Astronaut appeared first on Bedtime Math.

]]>It’s Memorial Day, a major holiday weekend that honors America’s veterans. A lot of schools end their year this week, and the kids who have finished all years of that school “graduate.” Well, what better person to give them a speech than an astronaut? That’s what happened last year at University of Connecticut. Astronaut Rick Mastracchio, who had gone to school at UConn himself, gave a speech to all the college kids from the International Space Station, 260 miles overhead. He gave part of the speech while floating upside-down, while the 400 UConn graduating students cheered. He told them he “has the best job on and off the planet,” and maybe some of those kids now want to become astronauts themselves.

*Wee ones:* If Rick turned upside down 3 times and squirted bubbles 4 times, which trick did he do more?

*Little kids:* Which was farther from the grads, the space station (260 miles away) or New York City (140 miles away)? *Bonus:* If the speech started at 1:05 pm and he had signal only until 1:15 pm, how many minutes did he have to speak?

*Big kids:* If *you* become an astronaut 20 years from now, how old will you be? *Bonus:* Rick was 54 years old when he gave that speech. If he graduated from UConn when he was 21, how many years earlier was that?

Answers:

*Wee ones:* Squirted bubbles.

*Little kids:* The space station! *Bonus:* 10 minutes.

*Big kids:* Different for everyone…add 20 to your age. *Bonus:* 33 years.

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]]>The post Wedding Cookie, or Wedding Cake? appeared first on Bedtime Math.

]]>Let’s call it what it is: this wedding cake is really just a pile of Oreos. But they’re stacked so carefully using math that the “cake” looks awesome when it’s done. Wedding cakes have to feed as many as 100 guests or even more. So the cakes often have 3 or more big “tiers,” or sections, with each smaller than the one below it. Usually it’s a fluffy baked cake, but if the bride and groom really love Oreos, this dessert is super easy to make. It starts with 4 layers of cookies in the 1st tier, laid carefully to fill a 12-inch circle. Each cookie sits half and half on the ones below it so the thing won’t tip over. Then the next tier has 4 9-inch-wide layers, and finally a 6-inch-wide tier on top. And you won’t believe how many Oreos end up in there!

*Wee ones:* The very top layer has 6 Oreos in a circle with 1 more in the middle. How many cookies is that in total?

*Little kids:* If each person wants 2 cookies, how many people can you fully feed from a layer of 7 cookies? *Bonus:* Which has more cookies, 2 of the little 7-cookie layers, or 1 medium layer of 20?

*Big kids:* If each big layer uses 40 Oreos, how many cookies are in just those 4 big layers? *Bonus: *How many giant packs of 50 Oreos do you need to finish that whole tier?

*The sky’s the limit:* If you have 4 layers with 7 cookies in each, 4 with 23 cookies each, and 4 with 40 each, how many Oreos does the whole cake use?? (Cool math hint if needed: To multiply many numbers by 4 and then add them, you can add them first, then multiply by 4…might be faster!).

Answers:

*Wee ones:* 7 cookies.

*Little kids:* 3 people, since 4 people would need 8 cookies. *Bonus:* The medium layer has more.

*Big kids:* 160 cookies. *Bonus:* You’ll need 4 packs, since 3 packs would give you just 150 cookies.

*The sky’s the limit:* It uses 280 cookies You can either add 28, 92 and 160 (4 times each layer), or else you can add 7+23+40 to get 70, then multiply that by 4.

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]]>The post When Your Tail Really Counts appeared first on Bedtime Math.

]]>Looks like these ring-tailed lemurs really want to learn how to use that camera. And in fact, it turns out these silly, stripy goofballs are pretty smart: they can do math! Lemurs can do basic counting and addition/subtraction, and can also remember a line-up of objects and put them in order from memory. Never mind the numbers in their wild long tails: the lemur’s tail always has 12 or 13 white rings and 13 or 14 black rings, and the tip always ends in black. The tail fits all those rings because it’s longer than the lemur’s whole body, but lemurs don’t use their tails to grab stuff. The tail mostly helps them balance as they leap through the trees. Lemurs live on the island of Madagascar off the coast of Africa, where they first showed up about 65 million years ago; there are now more than 100 types. It’s a beautiful place, so we can see why they’d like to learn photography.

*Wee ones:* If the lemur’s tail has a black ring at the tip, then white, then black, then white, what’s the next ring?

*Little kids:* If a lemur’s tail has 12 white rings and 13 black rings, of which color does it have more? *Bonus:* If the 1st ring is black followed by white, then black and so on, what color is the 12th ring?

*Big kids:* If a lemur has an 18-inch long body and its tail is 1/3 longer than that, how long is the tail? *Bonus:* How long is the whole lemur from head to tail tip?

Answers:

*Wee ones:* A black ring.

*Little kids:* More black rings. *Bonus:* White.

*Big kids:* 24 inches, since it’s 6 inches longer. *Bonus:* 42 inches.

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]]>The post Secret Swimming Pool appeared first on Bedtime Math.

]]>This may be the coolest swimming pool in the world — if you can find it. Artist Alfredo Barsuglia built it last summer in the middle of the Mojave Desert. To use the pool you have to open the cover with a key, which you pick up at the MAK Art Center in Los Angeles. With the key you’re told the “coordinates,” numbers that tell you where the pool is on a map. That’s it — now you have to find it. It’s often over 100 degrees in the desert, and the hot dry air makes the water “evaporate”, meaning it turns into tiny droplets that disappear into the air. That’s why the pool is covered all the time, and that’s why any visitor has to pour in a gallon of new water to make up for any water lost while swimming. It’s a lot of work, but once you’re there, you’ll want to cool off in the 100-degree heat.

*Wee ones:* If you and 5 friends go on a hunt to find this pool, how many of you go in total?

*Little kids:* If you drive 10 hours to LA to get the key, then drive 10 hours to the pool, how long have you driven? *Bonus:* If you then have to drive back to LA to return the key, now how long have you driven in total?

*Big kids:* A solar panel keeps the pool cool in the hot sun. If it chills the water down halfway from 100 degrees to 82 degrees, what temperature is the water now? *Bonus:* If there’s a visitor every other day this June and each one adds 1 gallon of water, how many gallons are poured in? (Reminder: June has 30 days.)

Answers:

*Wee ones:* 6 people.

*Little kids:* 20 hours. *Bonus:* 30 hours.

*Big kids:* 91 degrees. It drops 9 out of 18 degrees. *Bonus:* 15 gallons.

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]]>The post Don’t Trip Over that Tongue! appeared first on Bedtime Math.

]]>Who has the longest tongue? It may be 18-year-old Adrianne Lewis, whose tongue sticks out 4 inches past her mouth. She can lick her own nose, chin, eye, and even her elbow (just about no one can do this – try licking your own elbow). While most of our tongues are only 3 inches long in total, she thinks she stretched hers by sticking it out so much as a little kid.

But other animals kick our butts when it comes to tongues. The kinkajou, or honey bear, is a raccoon-like animal that’s only about 20 inches tall, but whose tongue sticks out 5 inches. That’s 1/4 as long as its whole body! The kinkajou uses that long tongue to slurp honey from beehives. But the real winner may be the anteater, whose tongue can be as long as its whole head and stick out 2 feet! The anteater uses it to eat, you guessed it, ants. We people would probably rather lick our eyeballs.

*Wee ones:* Whose tongue is longer, Adrianne’s 4-inch tongue or the kinkajou’s 5-inch tongue?* ** *

*Little kids:* If your tongue is 3 inches long and it needs to be 7 inches long to reach to the bottom of an ice-cream cone, how much longer a tongue do you need? *Bonus:* If your pet anteater’s tongue is 3 times as long as your 3-inch tongue, how long is it?

*Big kids:* If you lick your eye, then your chin, then your nose, then your elbow, then start over with your eye and keep repeating…which part do you lick on the 27th lick? *Bonus:* If your tongue were 1/4 as long as your whole body, how long would it be in inches? (Hint if needed: To divide by 4, you can cut the number in half, then cut in half again.)

*The sky’s the limit:* If your pet anteater’s body and its tongue are together 80 inches long, and the body is 3 times as long as the tongue, how long is each one?

Answers:

*Wee ones:* The kinkajou’s tongue.

*Little kids:* 4 inches longer. *Bonus:* 9 inches.

*Big kids:* Your nose, since it’s before your elbow which lands on all the multiples of 4 (including 28). *Bonus:* Different for everyone…divide your height (or the closets multiple of 4) by 4.

*The sky’s the limit:* The tongue is 20 inches, and the body is 60 inches. This is like our cheetah math problem: the body is like 3 tongues, so the body plus the tongue are like 4 tongues all together, adding up to 80 inches. So 1/4 of that 80 is 20 inches for 1 tongue.

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]]>The post Tomato-Chucking Robot appeared first on Bedtime Math.

]]>If you had to run a really fast race, would you want to carry a robot piggyback the whole way? You might, if that robot was going to feed you. That’s how the world got Tomatan, a tomato-tossing robot for marathon runners. A marathon is 26 miles long, and it’s really hard to run that far. So Tomatan helps out. It rides on the runner’s back and when the runner squeezes one of its feet, Tomatan grabs a tomato out of its own backpack, swings it overhead and holds it to the runner’s mouth. As we see in the video, the runner can just keep running while munching! You probably never thought you could have a backpack robot — but you also probably never thought you’d want to eat tomatoes while running. Now you can do both.

*Wee ones:* What shape is a tomato?

*Little kids:* If Tomatan could feed you 2 tomatoes and then 5 bananas, how many pieces of food would he hand you? *Bonus:* If the robot can carry only 10 tomatoes along with the bananas, how many tomatoes are left?

*Big kids:* If you run 26 miles and eat a tomato every 3 miles, can you eat all 10 tomatoes before you finish the race? *Bonus:* If you eat 2 tomatoes during each and every mile, how many do you chug down in total?

Answers:

*Wee ones:* It looks like a circle from the side, and it’s also a sphere (a ball)…or if you want to get fancy, a spheroid (a squashed sphere, since most tomatoes aren’t perfect).

*Little kids:* 7 pieces. *Bonus:* 8 tomatoes left.

*Big kids:* No: even if you eat one at the start (0 miles), you’ll have had 2 tomatoes after 3 miles, 3 after 6 miles, and so on, giving you only 9 by 24 miles. *Bonus:* 52 tomatoes.

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]]>The post We’ve Spotted Your Next Pet appeared first on Bedtime Math.

]]>Would you like to have one of these fuzzy, furry fellows as a pet? They’re 4-month-old cheetah cubs, and they already have their spots — because unlike most big cats, they’re born with them. While they’re awfully cute, though, they might be tricky as pets. For one, they weigh less than a pound when they’re born, but by this age they might weigh 30 pounds or more — and they can grow up to weigh almost 160 pounds. Never mind that cheetahs can run 70 miles an hour or faster, making it hard to chase them down if you forgot the leash. Then there’s the fact that they like to eat animals as big as 80 pounds, like young zebras and antelope (African mammals that look a bit like deer). But if you can keep up with all that work, these furry cubs might be the purr-fect pet.

*Wee ones:* If you’re counting a cub’s 4 furry paws, what numbers do you say?

*Little kids:* Mama cheetahs can give birth to as many as 9 cubs at once. If 3 are girls, how many are boys? *Bonus:* If it’s now May and the cubs are 4 months old, in what month were they born?

*Big kids:* If your regular housecat weighs 10 pounds and each cub weighs 5 times as much, how much do the 2 cubs weigh together? *Bonus:* If you’re making 1/2-pound burgers for dinner and each cheetah cub needs to eat 30 pounds of meat, how many burgers do you make for each cub?

*The sky’s the limit:* If your cheetah cub and your regular cat weigh 99 pounds together and the cub weighs 8 times as much as your cat at that point, how much does each furry friend weigh?

Answers:

*Wee ones:* 1, 2, 3, 4.

*Little kids:* 6 are boys. *Bonus:* In January.

*Big kids:* 100 pounds, since each weighs 50 pounds. *Bonus:* 60 burgers each!

*The sky’s the limit:* The cheetah weighs 88 pounds, and the cat weighs 11. If the cheetah weighs the same as 8 cats, together they weigh the same as 9 cats, so we divide 99 by 9 to get 11 for the cat. In algebra, we’d write:

c + 8c = 99

9c = 99

c =11, so the cheetah = 8c = 88.

And thank you to Lisa D. for taking this amazing photo and sharing it!

The post We’ve Spotted Your Next Pet appeared first on Bedtime Math.

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