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

]]>Do you know the famous building in the picture to the right? It’s the Empire State Building, once the tallest building in New York City. But the tiny wooden Empire State in the guy’s hand holds a world record, too: it’s the smallest Empire State ever. Steven Backman made this sculpture out of pieces of toothpicks, using just a razor blade, pliers, and glue. The teeny building is less than 1 inch tall and is perfectly “to scale,” meaning its height, length and width relate in the same way as for the real building…if the building is 20 times as tall as it is wide, so is this one. In the video he also shows off a tiny Big Ben (the famous London clock tower), the Golden Gate Bridge from San Francisco, and other toothpick buildings. We hope you didn’t need to clean your teeth!

*Wee ones:* What shape are the windows on the Empire State Building?

*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 12 is 2 x 2, x 3, so you can multiply in steps if you like.)

Answers:

*Wee ones:* Rectangles, and maybe even squares (rectangles with 4 equal sides).

*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 Super-Sticky Sandwich appeared first on Bedtime Math.

]]>The most popular sandwich in America might be the peanut butter and jelly. We’ve been making these sandwiches for over 100 years — the first known recipe is from the year 1896! It’s kind of silly that you’d need a recipe for spreading peanut butter on bread, but back in the day it was trickier than that: people had to make their own peanut butter at home. Another recipe from 1901 adds jelly to the mix. Then in 1928 sliced bread was invented, and then we knew everything we needed to know to make this easy sandwich. Today the average kid eats 1,500 PB&J sandwiches before graduating from high school — so that’s some pretty sticky math.

*Wee ones:* If you put a piece of bread on the plate, then top it with peanut butter, then jelly, then another slice of bread, how many layers do you have?

*Little kids:* If you make a mega-PB&J sandwich layering bread, then PB, then jelly, then bread again to repeat, what ingredient is the 6th layer? *Bonus:* Which layer of the sandwich is the 3rd layer of peanut butter?

*Big kids:* If the peanut butter sandwich came to life in 1896 and the jelly came along in 1901, how many years later was that? *Bonus:* If you eat 200 PB&J sandwiches each year, and you eat 1,600 by the time you graduate at age 17, how old were you when you started?

Answers:

*Wee ones:* 4 layers.

*Little kids:* Jelly. *Bonus:* The 8th layer, since the peanut butter is always 1 less than a multiple of 3.

*Big kids:* 5 year later. *Bonus: *Age 9, since it takes 8 years to eat 1,600 sandwiches at that rate.

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]]>The post As Purple As a Tomato appeared first on Bedtime Math.

]]>Tomatoes are red, carrots are orange, and bananas are yellow, right? Well, what do you do with a yellow tomato or a purple carrot? You line them up in a rainbow to make amazing pictures like this one. Photographer Brittany Wright gathered up all kinds of fruits and veggies, each in a whole range of colors, and laid them out by shade to make stripy designs, like these fun hot peppers. You can see them all here. Did you know that carrots were never orange on their own until about 400 years ago? They were always red, purple, yellow, or white, until the Dutch blended red and yellow to make orange for their royal family, the House of Orange. Now orange carrots look just fine!

*Wee ones:* If the citrus picture has grapefruits, oranges, lemons and limes, how many kinds of fruit is that?

*Little kids:* How many hot peppers can you count in the top picture? *Bonus:* If 5 of them have some green on their skin, how many don’t?* *

*Big kids:* The tomato photo on that page has 5 rows with 5 tomatoes in each. If you found 4 blue tomatoes to add on, how many would you have in total? *Bonus:* If you grab 12 carrots out of your fridge, and of those there are twice as many purple ones as orange ones (and no other colors), how many do you have of each color?

Answers:

*Wee ones:* 4 kinds of fruit.

*Little kids:* 12 peppers. *Bonus:* 7 peppers.

*Big kids:* 29 tomatoes, up from 25. *Bonus:* There are 8 purple and 4 orange carrots. The purple counts as 2 sets of orange, plus another set of orange makes 3 sets. So each “set” has 4 carrots, and purple ends up having 8.

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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 it turns out these silly, stripy goofballs are pretty smart: they can do math! Lemurs can count, add, and subtract, and can also line up objects in order from memory. Even their wild long tails have numbers behind them: the lemur’s tail always has 12 or 13 white rings and 13 or 14 black rings, and the tip always ends in black. Lemurs live on the island of Madagascar off the coast of Africa. It’s a beautiful place, so we can see why they’d like to take some pictures of it!

*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, then white, and so on, what color is the 12th ring?

*Big kids:* If a lemur’s tail has 27 rings, and there’s 1 more black ring than white ring, how many rings of each color? *Bonus:* If a lemur is 18 inches long and its tail is another 1/3 body length longer than that, how long is the whole lemur from head to tail tip?

*The sky’s the limit*: We can’t tell you how many rings a baby lemur’s tail has, but if you took that number, multiplied it by itself, and added 9, you’d get 58. How many rings does the tail have?

Answers:

*Wee ones:* A black ring.

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

*Big kids:* 14 black rings and 13 white. If you took off that extra black ring, you’d have 26 rings that are equally black and white, so then you just cut 26 in half to find the white. *Bonus:* 42 inches, since it’s 18 plus 24.

*The sky’s the limit:* 7 rings. If you walk backwards, the number times itself comes to 49 (58-9), and 49 is divisible only by 7, so that’s your answer!

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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 this backwards bike. When you turn the handlebars left, the bike turns right, and when you turn them, right, the bike curves left. Destin of Smarter Every Day built this bike 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! Guess what: he then tried to ride a regular bike and couldn’t do it anymore! He had to retrain his brain. 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. But feel free to try!

*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 starting in August, when did he finally succeed?

*Big kids:* If 3 people ride to the finish without falling down, how much money does Destin have to pay out? *Bonus:* If he has $1,000 in total to give as prizes, and you’re the first winner, how many more bike-riders could he pay at $200 apiece?

Answers:

*Wee ones:* You turn right.

*Little kids:* 8 feet. *Bonus:* The following April.

*Big kids:* $600. *Bonus:* 4 more riders, since he can handle 5 at most.

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

]]>Who has the longest tongue? It may be 20-year-old Adrianne Lewis, whose tongue sticks out 4 inches past her mouth. She can lick her own nose, chin, eyeball, and even her elbow. Just about no one can do that last one — try licking your own elbow! But some animals do much better. The honey bear’s tongue is 5 inches, when the whole bear is just 20 inches long — it’s 1/4 of its whole height! 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:* Try to lick your left elbow. Now try to lick your right elbow! Did you reach either one?

*Little kids:* If your tongue is 3 inches long and it needs to be 7 inches long to reach your eyeball, 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 eyeball, then your chin, then your nose, then your elbow, then start over with your eyeball to repeat…which part gets 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, which is 2 x 2, 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:* See if you can learn your right from left!

*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 closest multiple of 4) by 4.

*The sky’s the limit:* The tongue is 20 inches, and the body is 60 inches. The body is like 3 tongues, so the body plus the tongue are like *4* tongues all together. These 4 tongue lengths add up to 80 inches. So 1/4 of 80 is 20 inches for 1 tongue.

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]]>The post Is That a Cookie or a Cake? appeared first on Bedtime Math.

]]>Let’s call it what it is: this “wedding cake” is a pile of Oreos. But they’re stacked so carefully using math that the cake looks awesome when it’s done. Wedding cakes might have to feed 100 guests or even more. So the cakes often have 3 or more big “tiers,” or thick sections, with each smaller than the one below it. Usually it’s a fluffy baked cake, but this bride and groom must really love Oreos. And guess what: this dessert is super easy to make yourself! Check out the video to give it a try — and to see how fast the number of Oreos adds up.

*Wee ones:* What shape is an Oreo?

*Little kids:* If you eat 2 cookies from that crazy cake, then 2 more, then 2 more, how many have you eaten in total? *Bonus:* Which has more cookies, 2 of the little 7-cookie layers, or 1 medium layer of 15?

*Big kids:* If each big layer uses 40 Oreos, how many cookies are in just those 4 big layers? (Hint if needed: What if each layer used just 4 cookies? And how is this different?) *Bonus:* How many giant packs of 50 Oreos do you need to buy to have enough cookies for that whole tier?

Answers:

*Wee ones:* A circle, or in 3D, a very short “cylinder” (tube shape).

*Little kids:* 6 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.

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]]>The post Doggy Paddle Like a Pro appeared first on Bedtime Math.

]]>Do you know how to swim? It’s a very exciting moment when you finally learn how. Dogs seem to feel the same way, as in this video of 8 golden retriever puppies. Just like people, some take a while to dip in a paw, while a brave one jumps right in. Dogs love to swim, and golden retrievers are among the top 10 breeds (types) of dog that do it best. Poodles swim well, too — did you know that their name and the word “puddle” both come from the German word for “splash”? If you’d like to learn how to doggy paddle, learn from the pros!

*Wee ones:* Pretend you’re doing the doggy paddle. Paddle with your right “paw,” then your left paw!

*Little kids:* If 8 puppies go for a swim, what numbers do you say to count them? *Bonus:* If 8 puppies jump in, then 2 climb out, then 1 jumps back in, how many are now in the pool?

*Big kids:* How many swimming paws do those 8 puppies have? *Bonus:* If there are 20 legs in the pool including the 4 people training them, how many puppies are in?

*The sky’s the limit: *If there are 60 paws in the pool, and within that there are twice as many poodle paws as golden retriever paws, how many poodles are in the pool?

Answers:

*Wee ones:* See if you know your right hand from your left.

*Little kids:* 1, 2, 3, 4, 5, 6, 7, 8. *Bonus:* 7 puppies.

*Big kids:* 32 paws. *Bonus:* 3 puppies, since the people take up 8 legs, leaving 12 puppy legs.

*The sky’s the limit: *10 poodles (and 5 golden retrievers). If there are twice as many poodle paws as golden paws, it’s like having a set of golden paws plus 2 more equal sets of poodle paws, or 3 equal sets together. So we take 1/3 of 60, which is 20, giving us 20 golden paws. That leaves us 40 poodle paws on 10 poodle, since each dog has 4 paws.

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]]>The post Don’t Bite the Robot That Feeds You appeared first on Bedtime Math.

]]>This might be the weirdest robot we’ve seen yet. Tomatan is a tomato-tossing robot for marathon runners. A marathon is 26 miles long, and it’s really hard to run that far. When the runner squeezes one of Tomatan’s 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 you want to eat 10 things in total, how many more pieces of food should Tomatan feed you?

*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:* 3 more pieces.

*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.

The post Don’t Bite the Robot That Feeds You appeared first on Bedtime Math.

]]>The post High-Flying Jump appeared first on Bedtime Math.

]]>Jumping on a trampoline can make you feel like a superhero. Just one little push-off and you’re flying higher than anybody on the ground. With all that time hanging in the air, you can do flips, bounce onto your knees, or land in a handstand. There are world records for the longest time jumping, the most one-legged jumps, and even the “Fastest Time to Dress in Formal Attire While Jumping on a Trampoline.” Even dogs are getting into the act: check out this video of a Great Dane (a really huge dog) doing some jumps himself!

Answers:

*Wee ones:* 3 jumps.

The post High-Flying Jump appeared first on Bedtime Math.

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