The post Smiley Face in Space appeared first on Bedtime Math.

]]>When we look up at the stars, sometimes we see connect-the-dot clumps called constellations. Leo the Lion looks like a backwards question mark (his mane) with a triangle body, and the hunter Orion has a nice neat belt of 3 stars. A “telescope” helps you see much, much farther, the same way binoculars work, so it lets you see many more stars. So there was a “Hidden Treasures” contest to spot cool shapes in star photos from the Hubble Space Telescope, which floats high above Earth’s air. One skygazer, Judy Schmidt, spotted this great smiley face. Those bright eyes aren’t single stars — they are clusters of whole *galaxies*, each of which could hold millions of stars. The streaks come from stars moving while the telescope snapped the picture, giving us a perfect smile.

*Wee ones:* If you count the eyes and nose of the face, how many “dots” are you counting?

*Little kids:* If a smiley face had 2 star eyes, a star nose, and a 3-star mouth, how many stars would the face have? *Bonus:* How many stars would 2 faces have?

*Big kids:* If Judy found this in the 200th photo she studied, how many photos had she already searched? *Bonus:* If you drew a circle around every 5 stars to make a smiley face, how many faces would you find in a picture of 150 stars?

__Answers:__

*Wee ones:* 3 dots.

*Little kids:* 6 stars. *Bonus:* 12 stars.

*Big kids:* 199 photos. *Bonus:* 30 faces.

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]]>The post How to Mail a Coconut appeared first on Bedtime Math.

]]>When you’re eating a yummy snack and wish you could share it with a friend, wouldn’t it be great if you could just slap a stamp on it and stick it in the mail? It turns out you can, with one food: coconut. On the small Hawaiian island of Molokai, the Hoolehua Post Office gives out free coconuts for people to ship to their friends. No box, no envelope — you just stick a stamp onto the coconut. The “Post-a-Nut” postage costs between $9-13 depending on the coconut’s weight: If you shake a coconut and hear juice sloshing around inside, that means it’s still fresh enough to eat — but it will weigh more since it hasn’t dried out. For a fresh coconut snack, it’s totally worth it.

*Wee ones:* If you mail a coconut to each of 2 friends and grab one for yourself, how many coconuts do you get?

*Little kids:* If you could ship a coconut for $10 and a watermelon for twice as much, how much would it cost to ship the watermelon? *Bonus:* How much do you pay to ship both?

*Big kids:* 7,000 people live on Molokai. If each one sends a coconut to 3 friends, how many coconuts get shipped out? *Bonus:* If out of 400 nearby trees, 1/2 the trees grow 10 coconuts each while 1/2 grow 20 each, how many coconuts can the post office mail?

__Answers:__

*Wee ones:* 3 coconuts.

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

*Big kids:* 21,000 coconuts. *Bonus:* 6,000 coconuts: 2,000 from the first 1/2, and 4,000 from the 2nd set.

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]]>The post Chick-Tac-Toe appeared first on Bedtime Math.

]]>Have you ever played tic-tac-toe? You and another player fill in Xs and Os on a grid of 9 little squares, and the first person to fill in 3 Xs or Os in a straight line wins. Both kids and grown-ups can play it — and apparently chickens, too. For years a store in Chinatown in New York City had live chickens who played tic-tac-toe by pecking at a tic-tac-toe board on a table. They’d play against people, and the chickens often won! It turned out the chicks were getting some help: they were trained to peck at a spot of light, which a hidden person would shine on the best square. Even so, when those chickens won, they probably felt pretty proud.

*Wee ones:* If you watch 4 chickens play tic-tac-toe, what numbers do you say to count them?

*Little kids:* If you win your 1st game against the chicken, then the chicken wins twice, then you win twice, who has won more games? *Bonus:* If you’re playing tic-tac-toe against a chicken, and you’ve put an O and the chicken has pecked an X, how many of the 9 squares are still empty?

*Big kids:* If there are 5 chickens and each plays 8 games, how many tic-tac-toe games have they played? *Bonus:* If a chicken wins only every 4th game starting with the 4th, how does it do on the 34th game?

*The sky’s the limit:* If the chickens play 40 games and win 26 of them, then play 10 more and you win all 10 of those games, have the chickens still won at least half their games?

Answers:

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

*Little kids:* You have won more, since you’ve won 3 and the chicken has won 2. *Bonus:* 7 squares.

*Big kids:* 40 games. *Bonus:* The chicken loses, since 34 isn’t a multiple of 4.

*The sky’s the limit:* Yes! The chickens have still won 26 out of 50 games.

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]]>The post Big Burst of Bunnies appeared first on Bedtime Math.

]]>Bunnies are really cute, except when they take over your whole town. In South Fargo, North Dakota, big fluffy jackrabbits the size of small dogs showed up a couple of years ago, and had baby bunnies and more baby bunnies so fast that bunnies showed up everywhere. A woman in this video said that every morning she woke up to see 40-50 of them in her backyard! Why did this happen? In one year a mama jackrabbit can have babies 4 times, with up to 9 baby bunnies in each litter. And if the bunnies have no “predators” — animals who want to eat them — there’s nothing stopping the hopping.

*Wee ones:* How many bunnies can you count in the photo?

*Little kids:* If you see 5 bunnies in your driveway, how many ears do they have? *Bonus:* If the woman sees 8 bunnies under her picnic table, and 1 hops away, then another, then another, what numbers would you say to count down the number of bunnies left?

*Big kids:* If a mama bunny can have 4 litters of babies with 9 bunnies in each, how many bunnies does she have that year? *Bonus:* How many babies would 100 mama bunnies have that year?

Answers:

*Wee ones:* 9 bunnies.

*Little kids:* 10 ears. *Bonus:* 7 bunnies, then 6, then 5.

*Big kids:* 36 babies. *Bonus:* 3,600 baby bunnies!

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]]>The post You’ve Got Mail appeared first on Bedtime Math.

]]>It’s Valentine’s Day, when people all over America give each other flowers, balloons and chocolate to show that they love each other, even though we all actually love each other every day. They also give cards, and for kids who bring cards for their entire class at school, this becomes a pretty big project. You have to pick out a set of cards at the store or else make your own. Then you have to decide whether the boys and the girls all get the same kind of card, or should you give them different ones. Then there’s the matter of attaching a treat: should it be Hershey kisses, or pencils with hearts on them, or those candy hearts that say things like “I’m Yours”? If you like putting together Valentines, you can make this as complicated as you like…and if you do the math right, you’ll have a couple of treats left over for yourself.

*Wee ones:* If with your valentines you give out 10 heart stickers and 8 heart pencils, which treat did you give more?

*Little kids:* If your class has 23 kids including you, and everyone gives out valentines, how many valentines will you get? *Bonus:* If half of those valentines have a Hershey kiss in them, how many chocolate kisses do you get?

*Big kids:* If you have 23 kids in your class including you, and the valentines you want to get come in packs of 8, how many packs do you have to buy to have enough? *Bonus:* If the bag of Hershey kisses you buy contains 70 kisses, how many can you tape onto each valentine if you give the same number to everyone?

*The sky’s the limit:* Say you’re giving out 20 valentines, and you want to put 2 *different* treats in each one. If your choices are sparkly pencils, sticker sheets, and Hershey kisses, and half the kids get a pencil and 14 of them get a kiss, how many kids get a pencil and a sticker sheet?

Answers:

*Wee ones:* More stickers.

*Little kids:* 22 valentines. *Bonus:* 11 Hershey kisses.

*Big kids:* 3 packs, since 2 packs will give you only 16. *Bonus:* You can give each one 3, since that adds to 66 (and 4 apiece would come to 88, which you don’t have).

*The sky’s the limit:* You have to give kisses to as many non-pencil kids as possible, otherwise you’ll be stuck giving 2 sticker sheets to some kids, whereas they all have to get 2 different treats. So the 10 non-pencil kids get a kiss first, leaving 4 kisses. 4 pencil kids will get those kisses, leaving 6 pencil kids who get a sticker sheet instead.

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]]>The post Starting a Town by Accident appeared first on Bedtime Math.

]]>We love hearing about towns with silly names, and our fan Scott S. just told us about one we didn’t know: Accident, Maryland. How did it get its name? Apparently back in 1774, Lord Baltimore (for whom the big city is named) told people they could move onto his land in western Maryland. Two guys named William Deakins and Brook Beall headed to a certain creek, and started marking off the space they wanted — only to find out that they’d grabbed the same land “by accident.” They were buddies, so they didn’t fight over it — Deakins let Beall take the land. But it also turned out to be only 682 acres, not the 778 that Beall was supposed to get. So there was a math accident in there, too!

*Wee ones:* The town of Accident is roughly a rectangle. Can you find 2 things in your room that are rectangles?

*Little kids:* If there are 5 trees on your street block, and you pick out one for your treehouse, how many trees are left for other kids? *Bonus:* If you start building your treehouse on a Tuesday and finish 3 days later, when do you finish?

*Big kids:* If there are 24 trees in the park, and 10 kids come along and each picks a tree for a treehouse…then 18 more kids pick trees, at least how many “accidents” of picking the same tree have to happen? *Bonus:* The Accident accident happened in 1774. How long ago was that before the year 2017, when we heard about it here?

Answers:

*Wee ones:* Answers might include a shoebox, a book cover, a door, or the front of a dresser drawer.

*Little kids:* 4 trees. *Bonus:* On Friday.

*Big kids:* At least 4 accidents. *Bonus:* 243 years before.

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]]>The post Revenge of the Restaurant appeared first on Bedtime Math.

]]>Dinner is exciting when you’re hungry — but it can get a lot more exciting if you eat at any of the strangest restaurants in America. There was a restaurant decorated like a bathroom, where you sit on a toilet to eat (shown here). If that doesn’t sound good to you, other people agree, because it did go out of business. But you can still go to Harvey Washbangers, where you can do your laundry while you eat, and a giant board shows when your clothes have finished. You can eat with spies at the Safe House, or try Ninja New York, where your meal is served by ninjas who yell, wave swords, and do backflips. In all cases, your meal might be the least exciting part!

*Wee ones:* How many toilets can you count in the photo?

*Little kids:* If 3 ninjas take turns bringing you dishes in the same repeating order, and you order 5 dishes, how many times at most can any one ninja serve you? *Bonus:* If 10 ninjas work there and every other one can do backflips, how many backflipping ninjas are there?

*Big kids:* If at Harvey Washbangers it takes 32 minutes to wash your clothes and 25 to dry them, do you have a whole hour to eat dinner? *Bonus:* At Fritz’s Railroad Restaurant, your food is brought to you by a toy train on tracks above your head. If the train comes by every 12 minutes, how many times can it come by at most in 80 minutes?

*The sky’s the limit:* If you want to try eating in a bathroom, a laundromat, a ninja cave and a spy cave, in how many orders can you try those 4 restaurants?

Answers:

*Wee ones:* 4 toilets.

*Little kids:* 2 times at most. *Bonus:* 5 ninjas.

*Big kids:* Not quite, as that will all take just 57 minutes. *Bonus:* 7 trips. If it comes at every multiple of 12 (12, 24, 36, 48, 60, 72), that gives you 6 trips…but if the train first visits at minute 1 and then 1 minute later than each of these times, it will fit 7 trips.

*The sky’s the limit:* 24 orders. If the restaurants are B, L, N, S, you have 4 choices for your first meal. Once you go there, you have only 3 choices for your 2nd meal for each of those 4 1st choices, giving you 4 x 3 pairs. Then for your 3rd meal, you have only 2 choices left for any of your first 12 pairs. After that, there’s always only one choice left. That gives you 4x3x2x1 = 24. If you want to see the choices, they are BLNS, BLSN, BNLS, BNSL, BSLN, BSNL, giving 6 orders that start with the bathroom…then repeat this for each of the other 3 restaurants as your first!

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]]>The post One Tough Tortoise appeared first on Bedtime Math.

]]>Tortoises are pretty tough. They can live over 200 years, and can go 2 to 3 years without even eating! Even so, a family in Rio de Janeiro, Brazil was shocked when in their backyard shed they found their lost pet tortoise from 30 years ago, still alive and well. Manuela got lost one day when movers left the family’s front door open, and Manuela must have wandered out. How did she live for so long without help? She probably ate termites and other bugs, and drank water by licking “condensation” (the water droplets that show up on cold surfaces) off things in the shed. Manuela is a tough nut, but we bet she’s happy to be back in the house.

*Wee ones:* If you could last for 2 years without eating and you start now, how old will you be when you eat again?

*Little kids:* If Manuela is 50 years old right now, how old will she be a year from now? *Bonus:* If instead Manuela went missing 30 years and that was half her life, how old is she now?

*Big kids:* If you have a pet dog and a pet tortoise who’s 100 years older, and together their ages add up to 120, how old is each one? *Bonus:* If instead you have a pet tortoise who’s 12 times as old as you, how old is your tortoise?

Answers:

*Wee ones:* Different for everyone…add 2 to your age!

*Little kids:* 51 years old. *Bonus:* 60 years old.

*Big kids:* The dog is 10 years old and the tortoise is 110. *Bonus:* Different for everyone…multiply your age by 12!

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]]>The post Really Chilly Flowers appeared first on Bedtime Math.

]]>It’s pretty darn cold in parts of the U.S. right now, but believe us, it’s even colder in other places. The Arctic Ocean is way below freezing, with some spots around -2 degrees F. But thanks to the freezing cold, amazing ice shapes can grow, including these “frost flowers” that University of Washington professor Jody Deming and her student Jeff Bowman found. Just as frozen water sticks together to make lacy snowflakes, water droplets can pile up on floating ice to make these spiky shapes. We just hope the photographers like the cold — as we see here, they stood in that water to take the pictures!

*Wee ones:* The ice flowers are white. Try to spot 5 white things in your room.

*Little kids:* Which is colder, a day that’s 5 degrees F, or a day that’s 10 degrees F? (Lower numbers are colder.) *Bonus:* If the team took a 5-hour flight and a 6-hour boat ride to reach this chilly spot, how long did it take to get there?

*Big kids:* In the winter there, the sun barely peeks up above the water. If it shone for just the 2 middle hours of the day, when did the sun rise and set? *Bonus:* If Jeff is 6 feet tall and only 42 inches of him is above that freezing water, how much of his height is underwater? (*Reminder if needed:* One foot has 12 inches.)

__Answers:__

*Wee ones:* Items might include socks, bedsheets, pillow cases, and paper.

*Little kids:* The 5-degree day. *Bonus:* 11 hours.

*Big kids:* From 11:00 am to 1:00 pm, since noon (12 pm) is midday. *Bonus:* 30 inches, since he’s 72 inches tall.

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]]>The post Giraffe Wannabe appeared first on Bedtime Math.

]]>When you put cheese on a hamburger, you get a cheeseburger. When you combine a spoon with a fork, you get a spork. But what do you get when you put a zebra with a giraffe? You get something like the okapi, a strange animal from the middle of Africa. It has the stripes and short neck of a zebra, but is a closer cousin of the giraffe. Only its legs, tummy and butt have stripes, maybe so baby okapis can see and follow their mom through the tall grass. Like a giraffe, the okapi eats leaves from trees using its tongue, which is so long that an okapi can lick its own eyelids and ears to clean them! But unlike a giraffe, okapis stand only about 5 or 6 feet at the shoulder, while their giraffe cousins are about 3 times as tall. Maybe okapis feel like they fit in better with the zebras.

*Wee ones:* How many legs does an okapi have?

*Little kids:* If you pat a white stripe on the okapi, then a black stripe, then a white, then a black, what are the next 3 stripes you pat after that? *Bonus:* Baby giraffes start out tall. If a 6-foot okapi hangs out with his 11-foot baby giraffe cousin, how much taller is the giraffe?

*Big kids:* A giraffe’s tongue is about 20 inches long — almost 2 feet! If your tongue is 5 inches long (starting from the back of your head), how many of your tongue end to end would match a giraffe’s tongue? *Bonus:* We can’t tell you how tall our pet giraffe is, but if you take its height in feet, double it and add 5, you get 43. How tall is the giraffe?

*The sky’s the limit:* If giraffes, okapis and zebras are all hanging out together, and there are twice as many giraffes as okapis but twice as many striped animals as giraffes, and there are 12 more zebras than okapis, how many are there of each animal?

__Answers:__

*Wee ones:* 4 legs.

*Little kids:* White, black, white. *Bonus:* 5 feet taller.

*Big kids:* 4 of your tongue. *Bonus:* 19 feet.

*The sky’s the limit:* 6 okapis, 12 giraffes, and 18 zebras. If there are twice as many okapis and zebras together as giraffes, and the okapis are half the giraffe number, then the okapis are just 1/4 of the “stripe” total. Zebras have to cover the other 3/4. So there are 3 times as many zebras as okapis. That gap of 12 is like two more of those sets of okapis. That gives us 6 okapis and 18 zebras. That means there are 24 striped animals in total; giraffes are half of that, giving us 12 giraffes. So we did end up with twice as many giraffes as okapis.

The post Giraffe Wannabe appeared first on Bedtime Math.

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