The post Blue Sky, Blue Sea…Blue Trees? appeared first on Bedtime Math.

]]>No, this isn’t a picture out of a Dr. Seuss book. The trees in this photo are real, and they really are blue! A couple of years ago, artist Konstantin Dimopoulous painted these trees growing near a highway in Houston, Texas. He did the project to remind people that trees are disappearing from Earth, and that life could look very different if we don’t take care of them. The paint is safe for the trees and eventually washed off. Until then, it was kind of pretty, but also kind of weird. The real question is, how long did it take to paint them?

*Wee ones:* If you’ve painted 5 blue trees and your friend has painted 7 blue trees, which of you has painted more?

*Little kids:* If you’re 4 feet tall and your ladder lets you reach 5 feet higher than that, how high on these trees could you paint? *Bonus:* If a bigger ladder lets you paint up to 13 feet high on the tree, how much taller is the new ladder?

*Big kids:* If Konstantin painted 500 trees and used 2 one-gallon buckets of paint on each, how many buckets of blue paint did he use? *Bonus:* If he painted 100 trees each day starting on a Tuesday, on what day did he finish painting half the trees?

Answers:

*Wee ones:* Your friend has painted more trees.

*Little kids:* 9 feet high. *Bonus:* 4 feet higher, since 13 is 4 more than 9.

*Big kids:* 1,000 buckets of paint. *Bonus:* He finished the 250th tree on Thursday.

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]]>The post What It Takes to Be Superman appeared first on Bedtime Math.

]]>You’ve probably heard of superheroes like Batman, Spiderman, and so on. But the best of them all may be Superman, who first showed up in comic books in 1938. You may also know the famous words about him: “Faster than a speeding bullet, more powerful than a locomotive, able to leap tall buildings in a single bound.” So what does all of that really mean? The strength of a locomotive is measured in “horsepower,” where 1 horsepower can move a whopping 33,000 pounds 1 foot forward in 1 minute. A train engine can give you about 8,000 horsepower, so Superman is awesomely strong if he can match that. Meanwhile, bullets fly more than 1,000 miles an hour, and buildings can be more than 1,000 feet tall…even jumping over a 25-foot-tall house sounds like more than any of us can do!

*Wee ones:* If Superman could leap over your house and 3 other houses all at once, how many tall buildings did he leap in a single bound?

*Little kids:* If Superman leaps over a house, then a car, then a tree, then a house again to repeat the pattern…what does he leap over on his 8th jump? *Bonus:* If you rounded up 8,000 horses to pull a train as hard as Superman, how would you count them up by thousands?

*Big kids:* We also say “It’s a bird, it’s a plane, it’s…Superman!” The highest-flying bird, the bar-headed goose, can fly 21,000 feet high. If Superman can fly 10,000 feet higher than that, how high does he fly? *Bonus:* Commercial planes fly up to 45,000 feet at most. If Superman likes to fly halfway between the 21,000-foot bird and the plane, how high does he fly?

*The sky’s the limit — for real:* The Empire State building is 1776 feet tall, in honor of the year America declared independence. If Superman flies half that height in the 1st second, then half as far as that the 2nd second, then half as far as that the 3rd second, how high has he flown in 3 seconds? The numbers are pretty cool!

Answers:

*Wee ones:* 4 houses.

*Little kids:* A car. *Bonus:* 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000.

*Big kids:* 31,000 feet. *Bonus:* At 33,000 feet. If you ignore the thousands, you need the number halfway between 21 and 45. They are 45-21=24 apart, and half of that is 12, so you then add 12 to 21 to get 33 (or subtract 12 from 45).

*The sky’s the limit – for real:* 1554 feet. He flies 888 feet the 1st second, then another 444 feet, then another 222 feet.

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]]>The post Giant Family for a Giant Tortoise appeared first on Bedtime Math.

]]>Living for 80 years sounds like a long time to us humans. But this 80-year-old Galapagos tortoise is only halfway through life. As our friends Tyler and Ally M. just shared with us, last week Nigrita the tortoise just had babies for the first time! She hatched 9 mini tortoises, having laid the eggs earlier this year. The babies are very special because Galapagos tortoises are endangered. Galapagos tortoises can live to 150 years old. It’s the largest tortoise, as it can weigh more than 900 pounds! And while we’re at it, what’s the difference between a tortoise and a turtle? After all, they’re both reptiles, so they both breathe air and lay eggs. Turtles, though, spend most of their time in the water, while tortoises live on dry land. In fact, tortoises are pretty bad swimmers. But since they live to 150 years old, they get the last laugh.

*Wee ones:* If you’ve counted 5 of the baby tortoises, what numbers do you say to count the next two babies?

*Little kids:* If you have 3 pet tortoises, 2 pet turtles and a pet snake, how many pet reptiles do you have? *Bonus:* If Nigrita hatches 9 babies this year, 6 babies next year, 10 the year after that, then 7 the year after that…what number would she hatch next to keep the pattern?

*Big kids:* How many scaly feet do those 9 baby tortoises have all together? *Bonus:* Who weighs more, 9 baby tortoises who’ve grown to 80 pounds each, or their 700-pound mom?

Answers:

*Wee ones:* 6 and 7.

*Little kids:* 6 pet reptiles. *Bonus:* 11 babies.

*Big kids:* 36 feet. *Bonus:* The 9 baby tortoises, since they weigh 720 pounds together.

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]]>The post Watch Out for Space Junk appeared first on Bedtime Math.

]]>Our friend Chloe H. asked us a great question: how many times could you fly around the world in a spaceship in one day? It turns out it’s a lot. Satellites, the floating pieces of equipment that beam phone calls and videos to us, fly at 17,000 miles an hour. So they orbit around Earth in just an hour and a half! If you rode one of those, you’d make the trip around Earth 16 times in one day.

But at these speeds, we’re starting to have a big problem: space junk. Some of those satellites don’t even work anymore, but there’s no way to bring them back down. There are also leftover pieces from rocket boosters, tools dropped during astronaut walks, and so on. There’s so much junk up there that things are starting to crash into each other, splitting into thousands of tiny, dangerous pieces. At 17,000 miles an hour, even a tiny flake of paint can make a hole in a solar panel. If you’re up there doing a space walk, watch out!

*Wee ones:* If you have 4 pieces of space junk, and 1 of them breaks in half, how many pieces do you have now?

*Little kids:* If you’ve made 9 trips around Earth so far today, what number is your next trip? *Bonus:* How many more trips after that can you make today if you can make 16 trips in total?

*Big kids:* If you start your orbit at 3:30 pm and the trip takes 1 1/2 hours, at what time will you finish? *Bonus:* If there are 40 pieces of space junk in your path, and on each of your 16 trips today you scoop up 3 pieces, can you catch them all?

*The sky’s the limit:* If you start orbiting Earth today (May 24) and make 16 junk-collecting trips each day, on what date will you make your 100^{th} orbit?

Answers:

*Wee ones:* 5 pieces.

*Little kids:* The 10th. *Bonus:* 6 more trips.

*Big kids:* At 5:00 pm. *Bonus:* Yes! You’ll be able to catch 48 pieces.

*The sky’s the limit:* On May 30. You finish 16 trips today, and another 80 trips 5 days after today, which is May 29. That brings you to 96 trips, so the 100th trip happens on May 30.

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]]>The post A Day for Lucky Pennies appeared first on Bedtime Math.

]]>“See a penny, pick it up, and all day you’ll have good luck!” Today in America we celebrate National Lucky Penny Day: even though we’re not *sure* a penny can bring us luck, we might as well give it a try. In America 100 pennies makes a dollar, so 1 penny by itself can’t buy you much. A long time ago, though, it used to be worth a lot: back in the 1800s a penny could buy a candy bar, sheets of paper, and pieces of cloth to make clothes. Thanks to “inflation” (money becoming weaker over time), a penny doesn’t buy you much today. Now you might need 50, 70, or even 100 pennies to buy a candy bar. Pennies have such small value that people put them in penny-crushing machines to stamp pictures on them, like the one shown here — and they pay an extra 25 cents along with it to run the machine! The question is, will that penny still bring you good luck?

*Wee ones:* What shape is a real, unsquashed penny?

*Little kids:* If you put in the penny plus 25 cents to make a stamped penny, how much money do you spend in total? *Bonus:* If you have 31 cents on you, is that enough money to make one?

*Big kids:* If you’ve been collecting lucky pennies, and just 1 more will bring you to 1 dollar (100 pennies), how many do you have? *Bonus:* If you have 85 cents, how many funny squashed pennies can you make, and how much money will you have left over?

Answers:

*Wee ones:* A circle – and in 3D, it’s actually a very short, squat cylinder.

*Little kids:* 26 cents. *Bonus:* Yes! 31 is more than 26.

*Big kids:* 99 pennies. *Bonus:* 3 squashed pennies, which will cost 78 cents (25+25+25+1+1+1). You’ll have 7 cents left over.

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]]>The post Lego by the House-ful appeared first on Bedtime Math.

]]>Lego is one of those toys that every kid has heard of, and that almost every kid has played with. Ever since it was invented in 1958, Lego pieces have had the exact same thickness of brick, and the same size studs (the little bumps on top). They’ve made 4* billion *minifigures since then, which equals half the world’s population! Now they design 130 new sets each year, like the Star Wars sets, plus they keeping selling the longtime sets. So our longtime fan Benjamin H. asked, how many Lego pieces are made every day? Lego’s website says that in one year they make 45.7 billion Legos. If we divide by 365, that comes to 125 million pieces a day, and a bout 5 million every hour. Given that a 1-foot cube can hold only about 400 pieces, you can imagine how many houses you can fill every day with Lego!

*Wee ones:* If you snap together a Red Lego brick, a blue brick, a green, a yellow, a white and a black, how many bricks have you snapped together?

*Little kids:* If a Lego brick has 2 rows with 4 studs each, how many studs does it have? *Bonus:* If you snap a 2-stud piece on top, how many studs from the bottom piece are still showing?

*Big kids:* To find how many 1-foot cubes a room can hold, you just multiply the length times the width times the height to the ceiling. If your bedroom is 10 feet by 10 feet with an 8-foot ceiling, how many cubic feet of Lego can you fill it with? *Bonus:* If each cubic foot can hold 400 pieces, can the room hold all the Lego made in 1 hour? (Hint if needed: What if each cubic foot held only 4 pieces…then try 40 pieces…)

*The sky’s the limit:* How many different rectangle shapes (number of studs across and front to back) can a piece with 36 studs on top have? (Assume that you have at least 2 studs in either direction, but you don’t have to worry about which way each combo is facing.)

Answers:

*Wee ones:* 6 bricks.

*Little kids:* 8 studs. *Bonus:* 6 studs — or 7 if the 2-stud piece is hanging off the edge.

*Big kids:* 800 cubic feet. *Bonus:* That room holds 320,000 pieces…so you’d need more than 15 bedrooms that size to hold the Lego made in 1 hour!

*The sky’s the limit:* There are 4 ways: 2 studs x 18 studs, 3 x 12, 4 x 9, and 6 x 6.

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]]>The post Magical Midnight Moon appeared first on Bedtime Math.

]]>Some nights our Moon is just a white half-circle in the sky, or even a thin crescent (C shape). But tonight we get a treat: we have a full moon. Why does this happen? The Moon takes about 29 days to go around Earth, and when it’s on the opposite side of Earth from the Sun, we see its shiny side. When it’s between us and the Sun, its shiny side is away from us, so we can’t see it. That’s a “new moon.” When the Moon is “next to” Earth, we see half of it lit. What’s really cool is that whatever part of the moon is lit, that’s the fraction of the night we can see it! A full moon is up all night, and a half moon is up for half of it. It’s amazing that that bright ball is a quarte*r million* miles away from us. So our friend Isaac I. asked, how many pencils would we have to line up to reach the Moon? Even if they’re the giant pencils from last night, it’s a big number — and if we use regular pencils, it’s even more!

*Wee ones:* Tonight the Moon looks like a full circle. Can you see other circle shapes in your room?

*Little kids:* The Moon looked pretty full last night also, and will tomorrow night, too. If today is Saturday, what day was it yesterday, and what day is tomorrow? *Bonus:* The new moon will be 15 days from today (Saturday). What day of the week will that be?

*Big kids:* How do you write “1 million” all in numbers? *Bonus:* This is a big one…If our pencils are a little shorter than 1 foot, we can estimate that a mile (5,280 feet) can fit 8,000 pencils. How many pencils does it take then to reach a quarter million miles? (Hint if needed: How many would fit in 1 million miles? and then work from there.)

Answers:

*Wee ones:* Different for everyone…you might find clocks, balls, wheels on toy cars, eyes on stuffed animals. See what else you find!

*Little kids:* Yesterday was Friday, and tomorrow is Sunday. *Bonus:* On a Sunday. It’s 1 day more than 2 weeks, which would bring us to another Saturday.

*Big kids:* 1,000,000. *Bonus:* 2 billion pencils (2,000,000,000) since 1 million miles would hold 8 billion (8,000,000,000).

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]]>The post Whatever Floats That Big Boat appeared first on Bedtime Math.

]]>Boats can float in any size. It could be the toy boat splashing in your bathtub, or a real rowboat for 2 people. Then there are cruise ships that hold thousands of people, like an apartment building on water. But we can always build bigger. This week a huge new ship, the Harmony of the Seas, docked in England to get ready for its first voyage. The Harmony stretches 1,188 feet long — a whole 330 feet longer than the Titanic, the famous giant ship that sank in 1912. It can hold 8,880 people, including 2,100 crew members to take care of everyone. Best of all, it has the world’s tallest water slide at sea, a fish-shaped pair of tubes that start 10 stories high. For anyone who’s looking for excitement, that sounds a lot better than jumping overboard.

*Wee ones:* If you’re zooming down that water slide, what numbers do you say to count the 10 stories as you fall?

*Little kids:* On Sunday the ship will make its first trip, a 4-day voyage to the Netherlands and back. On what weekday will it come back if Sunday counts as its 1st day? *Bonus:* The water slide is 100 feet tall. If it starts 500 feet above the ocean, how far above water do you end your ride?

*Big kids:* It took 32 months to build this ship! If it finished in May 2016, when did the building start? *Bonus:* If 2,100 of the 8,880 people on board work as crew members, how many actual paying passengers get to ride the ship?

Answers:

*Wee ones:* 1, 2, 3, 4, 5, 6 ,7, 8, 9, 10.

*Little kids:* On Wednesday. *Bonus:* 400 feet.

*Big kids:* September 2013. 32 months is 2 years 8 months; 2 years ago was May 2014, so we then count 8 months back. *Bonus:* 6,780 passengers.

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]]>The post The Write Stuff appeared first on Bedtime Math.

]]>When you pick up a pencil to write, it feels like it weighs almost nothing. But the world’s biggest pencil probably takes a lot more work than that. So our friend Nya W. asked, how big is the world’s biggest pencil? (And drew this great picture to go along with it!) It turns out 2 pencils have set records. The world’s *longest* pencil stretched 1,509 feet, which is a good part of a mile. Made in August 2015, it was just as skinny as a real pencil, just really, really long. It was also rubbery and bendy, so it didn’t feel like the ones in your desk. The* biggest* pencil that looks like a giant real one was made just a few months later in New York City. At 76 feet long, it weighed 18,000 pounds! The eraser by itself was 2 1/2 feet long, and the lead — the dark part down the middle that leaves marks on the paper — was 10 inches across and weighed 4,500 pounds by itself. Next time you need to write a note to someone, you might want to stick with the pencils in your desk.

*Wee ones:* If you’re holding the world’s longest pencil, the world’s biggest pencil, and your own little pencil, how many pencils do you have?

*Little kids:* Who’s taller, that 76-foot pencil or a 29-foot-tall house? *Bonus:* If you use up 1 foot of that 1,509-foot pencil by drawing, now how long is it? See if you can remember the whole number!

*Big kids:* The eraser made up 2 1/2 feet of that giant 76-foot pencil. How long was the rest of it? (*Hint if needed:* What if the eraser were just 2 feet?) *Bonus:* If you write your name in letters half as tall as that 76-foot pencil, how tall are those letters?

*The sky’s the limit:* If a kid can pick up 50 pounds, how many kids would it take to pick up that 18,000-pound pencil? (*Hint if needed:* What if each kid could pick up 100 pounds?)

Answers:

*Wee ones:* 3 pencils.

*Little kids:* The pencil is taller! *Bonus:* 1,508 feet.

*Big kids:* 73 1/2 feet. *Bonus:* 38 feet — still probably taller than your home!

*The sky’s the limit:* 360 kids. If each could pick up 100 pounds, you’d need just 180 kids, but if each can lift only half of that, you’ll need twice as many people.

The post The Write Stuff appeared first on Bedtime Math.

]]>The post A Quick Drink for a Big Dog appeared first on Bedtime Math.

]]>It’s much easier to be a person than a dog. When you’re thirsty, you can fill a glass with water from the faucet. But a dog has to wait for someone to see that he’s thirsty, and fill his bowl. Well, not this Great Dane here — he doesn’t wait around. He figured out how to step on the water fountain pedal to make water come out, so now he just drinks from there! Great Danes are one of the biggest breeds of dog. They can stand almost 3 feet tall at the shoulder, and can weigh up to 200 pounds. These huge dogs look a little scary, but Great Danes are very sweet and gentle with kids. And this one is polite: as we see in the video, he’s nice enough not to lick the faucet while drinking. After all, we thirsty humans need to use that fountain, too.

*Wee ones:* If the Great Dane slurps up 7 sips of water, what numbers do you say to count them?

*Little kids:* If the dog starts the water fountain with his left paw, then his right, then his right again, then starts over with his left paw, then his right…which paw does he use on the 6^{th} try? *Bonus:* If that Great Dane weighs 200 pounds and his puppy friend already weighs 100 pounds, how much do they weigh together?

*Big kids:* If a Great Dane is 34 inches tall at the shoulder and the top of his head is 10 inches above that, who’s taller, you or the dog? *Bonus:* Every 2 cups of water weighs 1 pound (16 ounces). If the Great Dane weighs 180 pounds, then slurps up 8 cups of water, how much does he weigh on the scale now if he doesn’t pee first?

Answers:

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

*Little kids:* The right paw. *Bonus:* 300 pounds.

*Big kids:* Different for everyone…see if you’re taller or shorter than 44 inches! *Bonus:* 184 pounds, since the 8 cups of water weigh 4 pounds.

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