The post A Fast 500 Miles appeared first on Bedtime Math.

]]>It’s fun to drive fast on a highway, but that’s nothing like driving a racecar. Today Indianapolis will hold the 100th run of one of the most famous car races, the Indy 500. The cars speed around the track 200 times to drive 500 miles, which is how the race got its name. With the cars driving 200 miles an hour, it’s very exciting to watch. More than 100,000 people watch the race in person every year…if you lined up their seats in 1 long row, it would stretch for 99 miles! It takes more than 40 ice cream stands and 35 pretzel sellers to feed all those fans. On race day they sell more than 10,000 pounds of hamburgers, which need enough ketchup to fill 10 bathtubs. And of course there’s the gasoline, because the cars get hungry, too!

*Wee ones:* The Indy 500 had its actual 100th *birthday* in 2011 (it didn’t run every year). Were you alive yet that year?

*Little kids:* If you filled your bathtub(s) in your house with ketchup, how many more would you need to match the 10 tubs at the Indy 500? Count up your bathtubs! *Bonus:* 3 people in history have each won the Indy 500 4 times. How many races have they won altogether?

*Big kids:* The 33 cars line up in rows of 3 at the start. If you’re stuck in the next-to-last row, what number row is that? *Bonus:* If each car burns 20 gallons of gas in the race, how much gas do they use together? (*Hint if needed:* What if each car used just 2 gallons? And how does 20 gallons differ from that?)

*The sky’s the limit:* The 200 laps around the track add up to 500 miles. If you wanted to try driving just 10 miles of it, how many times would you have to drive around the track?

Answers:

*Wee ones:* Different for everyone…if you will be at least 5 years old as of May 29, then you were around for the 100th birthday!

*Little kids:* Different for everyone again…count up your bathtubs, then subtract from 10. If you have 10 or more, you don’t need any more tubs to match. *Bonus:* 12 races.

*Big kids:* The 10th row, since there are 11 in total. *Bonus:* 660 gallons.

*The sky’s the limit:* 4 laps. If you cut the 500 miles into 200 pieces (the laps), you find that the track is 2 ½ miles long. So you’d need 4 laps to drive 10 miles. Another way to solve it: 10 miles is 1/50 of 500, so you need to drive 1/50 of 200 laps.

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

]]>You’ve probably heard of 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 Freedom Tower in New York City is 1776 feet tall, in honor of the year America became its own country. 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 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 of the 500 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 Watch Out for Space Junk appeared first on Bedtime Math.

]]>Our friend Chloe H. asked us, 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 metal that send phone calls and videos to us, fly at 17,000 miles an hour. So they fly around Earth in just an hour and a half! But at these speeds, we have a new problem: space junk. Some of those satellites don’t work anymore, but there’s no way to bring them back down. There are also floating leftover pieces from rocket boosters, tools dropped during astronaut walks, and so on. Now these things are starting to crash into each other. If you’re up there doing a space walk, grab some garbage to help us clean up!

*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 1 penny by itself can’t buy much. Back in the 1800s, though, it used to be worth a lot: 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 in’t worth very much today. Now you might need 50, 70, or even 100 pennies to buy a candy bar. That’s why people happily 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 find a penny each day — Sunday, Monday, and so on — how many do you find in 1 week? *Bonus:* If you put in the penny plus 25 cents to make a stamped penny, how much money do you spend in total?

*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 if it costs the extra 25 cents to stamp one, 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:* 7 pennies. *Bonus:* 26 cents.

*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 knobs (bumps) each, how many knobs does it have? *Bonus:* If you snap a 2-knob piece on top, how many knobs 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 1 million Legos? Can it hold the amount made in about an 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 knobs across and front to back) can a piece with 36 knobs on top have? (Assume that you have at least 2 knobs 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 knobs. *Bonus:* 6 knobs — or 7 if the 2-knob piece is hanging off the edge.

*Big kids:* 800 cubic feet. *Bonus:* That room holds 320,000 pieces…so no, it doesn’t hold 1 million…and you’d need more than 15 bedrooms to hold the more than 5 million Legos made in 1 hour!

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

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]]>The post Tricky Triangles appeared first on Bedtime Math.

]]>The word “puzzle” can mean a lot of things: peg puzzles, number games, and jigsaws with squiggly pieces. But our favorite at Bedtime Math is the “tangram.” This ancient Chinese puzzle uses 7 shapes that you move around to match a picture. The picture gives no clues about where the shapes go — you have to figure that out! Here we’ve made this turtle by lining up the shapes as shown. The 7 shapes fit with each other in a special way: the medium triangle is the same size as 2 tiny triangles put together, and a big triangle is the same as 2 medium ones. The square and parallelogram also each equal 2 tiny triangles. Check out this page to print and cut out your own tangrams, and to match some puzzles yourself!

*Wee ones:* Point to all the triangles in the picture. What colors are they?

*Little kids:* If 2 tiny triangles make a medium triangle, and 2 medium triangles make a big triangle, how many tiny triangles do you need to make a big triangle? *Bonus:* The 2 tiny triangles against the green square make a shape called a “trapezoid.” Imagine that shape is all one color. How many sides does it have?

*Big kids:* How many tiny triangles can you fit in the whole big square that holds all the shapes? (*Hint: *the whole big square can fit 4 big triangles.) *Bonus:* If a giant tangram square covers 128 square inches, how much area does each tiny triangle cover? Can you figure out a handy way to divide by that number?

Answers:

*Wee ones:* Red, purple, pink, blue, and orange.

*Little kids:* 4 tiny triangles, since it takes 2 pairs. *Bonus:* 4 sides. It’s a “quadrilateral” just like squares and rectangles!

*Big kids:* 16 tiny triangles. *Bonus:* 8 square inches. To divide by 16, you’re just cutting in half 4 times in a row, since 16 is 2 x 2 x 2 x 2.

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]]>The post A One-Squiggle Cat appeared first on Bedtime Math.

]]>Cats are cute, but what’s weird about this drawing of a cat? If you look really, really closely, you’ll see that the whole thing is 1 single line! The line keeps bending in on itself to fill the paper. In places where the line pieces come close to each other, the picture becomes darker. Those different shades of color make it look like a picture of a real thing. This kind of line is called a Hilbert curve. As we see in this video, the artist actually programmed a printer to draw those squiggles. Cats may have 9 lives, but we don’t have enough lives to draw that whole long line ourselves!

*Wee ones:* Try drawing as straight a line on paper as you can. If you’re able, try to draw 2 straight lines close together without them touching!

*Little kids:* If you draw a line to make a shape with 5 sides, what do you call that shape? *Bonus:*If you draw 9 straight, non-crossing lines all in the same direction, how many spaces do they make between them?

*Big kids:* If a picture is 2 feet across and each squiggle is 1 inch wide, how many squiggles fit across the page? (*Hint if needed:* A foot has 12 inches.) *Bonus: *A 4-inch-wide square would hold 4 1-inch squiggles across and 4 squiggles up and down, giving us 16 squiggles. How many squiggles would fit in that square if the squiggles were just 1/2 inch tall and 1/2 inch wide?

Answers:

*Wee ones:* Try drawing a straight line, or two!

*Little kids:* A pentagon. *Bonus:* 8 spaces.

*Big kids:* 24 squiggles, since 2 feet = 24 inches. *Bonus: *64 squiggles, since you can now fit 4 of them (not 2!) in each square inch. Another way to think of it: you can now fit 8 squiggles across and 8 down.

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

]]>When you pick up a pencil, it weighs almost nothing. But our friend Nya W. asked, how big is the world’s biggest pencil? (and drew this great picture for us!) It turns out 2 pencils have set records, and they could both crush your hand. The world’s *longest* pencil stretched 1,509 feet, almost 1/3 of a mile. It was as skinny as a real pencil, just really, really long. The* biggest* pencil that looks like a bigger real one was shorter, but at 76 feet long it weighed 18,000 pounds! The eraser by itself was 2 1/2 feet long, and the lead — the dark middle part that marks the paper — was 10 inches across and weighed 4,500 pounds by itself. You might want to stick with the pencils in your desk.

*Wee ones: *Find a pencil (or pen or crayon) and hold it against your longest finger so they start at the same spot at one end. Which one is longer?

*Little kids:* If you line up 7 pencils in a row, which number pencil is exactly in the middle? *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 and subtract 1!

*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 long?) *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: *Either the pencil or your finger could be longer.

*Little kids:* The 4th pencil. There are 3 pencils on either side of it. *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.

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]]>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 fill his bowl. Well, this Great Dane doesn’t want to wait. 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 dog breeds. 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!

*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 next? *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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