The post The Secret to Dice appeared first on Bedtime Math.

]]>Dice are a fun toy we can use in a lot of different games. That’s because when you throw dice, you don’t know what will happen. A die is just a cube, a shape that has 6 flat square sides, or “faces.” Each face has some number of dots on it: one side has 1 dot, another has 2 dots, and so on up to 6 dots. The die can land with any of those faces pointing up. That tells you how many spaces to move in a board game, or whether you rolled a bigger number than your friend. And here’s a cool fact: on most dice, the two sides opposite each other always add up to 7. Find a die or two and check it out!

*Wee ones:* Find a box in your room that has 6 faces (flat sides). See if you can count them all.

*Little kids:* One side of a die has 2 rows of 3 dots in each. They’re sometimes called “railroad tracks.” How many dots are there in total? *Bonus:* Opposite sides on a die add up to 7. If you’re looking at the side with 5 dots on it, how many dots are on the opposite side?

*Big kids:* If you roll 4 dice, what’s the biggest number of dots you can roll in total? *Bonus:* If you roll a 3, 4, 5 and 6, which die would have to change to a 2 for your total to be 14?

__Answers:__

*Wee ones:* Count the 6 faces…remember to count the back side and the bottom!

*Little kids:* 6 dots. *Bonus:* 2 dots.

*Big kids:* 24. *Bonus:* You rolled 18, so to get 14 you need to lower the total by 4. So you change the 6 to a 2.

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]]>The post Invasion of the Lionfish appeared first on Bedtime Math.

]]>Lionfish are — you guessed it — fish that kind of look like lions. These spiky, stripy sea creatures are beautiful, but they’re poisonous. Worse yet, they’re taking over the Atlantic Ocean. They don’t normally live in the Atlantic, so they have no “predators,” or animals that like to eat them (this is where being poisonous comes in handy). They just keep having new baby lionfish, who have more baby lionfish. One lionfish can lay 30,000 eggs at a time! So they’re eating up 90% of the fish that live in Bermuda’s coral reef. Luckily, lionfish are very tasty to us people, and we can eat them without being poisoned. The question is, can we eat up all these fish before they eat everyone else?

*Wee ones:* How many white-tipped spiky fins does this fish have along the top? Count them up!

*Little kids:* If every other fish you catch is a lionfish, starting with the 2nd fish, is your 9th fish a lionfish? *Bonus:* How many lionfish have you caught by then?

*Big kids:* All lionfish appear to be the great-great-great…grandchildren of just 1 of a set of 6 fish. If those 6 fish each laid 30,000 eggs, how many new baby fish did they have in total? *Bonus:* If 25 restaurants in Florida each serve 2 lionfish each night, how many fish can they all serve in a week?

__Answers:__

*Wee ones:* 11 fins.

*Little kids:* No, it’s some other kind of fish. *Bonus:* 4 lionfish (the 2nd, 4th, 6th and 8th).

*Big kids:* 180,000 fish. *Bonus:* 350, since together they serve 50 per night.

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]]>The post Counting Stars with the Cows appeared first on Bedtime Math.

]]>Our friend Liam F. asked a great double-question: how many stars are in the universe, and how many can we see? Well, our own Milky Way “galaxy,” or clump of stars, has around 100 billion stars, and there are billions of galaxies out there…one astronomer guesses it’s a 1 with 24 zeroes after it (1,000,000,000,000,000,000,000,000 stars, or 1 septillion). So how many can we see with the naked eye? If you’re near big-city lights, the night sky won’t turn very dark, so you’ll see only about 500 stars on a clear night. Out in the countryside, though, the night sky will sparkle with stars — you might see up to 15,000! If you can drive at least 200 miles from a city, you and the cows will have many more stars to count.

*Wee ones:* Look out the window after dark. Can you see any stars in the sky? If you can’t, you can try again tomorrow night!

*Little kids:* If you can see any stars out your window, try to count as many as you can. *Bonus:* If you can see 10 stars tonight but twice as many tomorrow, how many will you see tomorrow?

*Big kids:* Leo the Lion has 6 bright stars in his question-mark-shaped mane, and 3 more in his triangle body. If in a darker sky Leo shows 4 times as many stars, how many can you see then? *Bonus:* You can divide the sky into equal-ish pieces, then count the stars in 1 piece to guess the whole sky. If you see 20 stars in each of 30 big pieces, how many stars can you see in total? (Hint if needed: What if there were just 2 stars in each piece?)

*The sky’s the limit — for real:* Which sky has more stars: a sky where you see 100 stars in each of 100 pieces, or a sky with 40 stars in each of 300 pieces?

__Answers:__

*Wee ones:* Different for everyone…see if you can spot at least 1 bright star! It might be a planet if it isn’t twinkling.

*Little kids:* Again, different for everyone…try it on a clear night. *Bonus:* 20 stars.

*Big kids:* 36 stars, since Leo has 9 bright ones. *Bonus:* 600 stars.

*The sky’s the limit:* The sky with 40 each in 300 pieces. That one has 12,000 stars, while the other has just 10,000.

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]]>The post You’ll Be Taller Tomorrow Morning! appeared first on Bedtime Math.

]]>Kids grow, because they haven’t reached full height yet. So our fan Andrew O. asked, how much can you grow *overnight*? For starters, you stretch about 1/2 inch every night while you sleep, and during the day you shrink back down 1/2 inch. Why? Because of “gravity” pulling down all day and smushing your body. Astronauts actually grow up to 2 inches when they float in space! But on top of that, your body might actually grow taller. We now know that kids don’t grow at the same speed all the time: their long bones grow really fast for short bursts, growing up to 1/2 inch in one day or night. Luckily, in between those spurts you might hardly grow at all. Good thing, or you’d shoot through the ceiling by next month!

*Wee ones:* Find the tallest thing in the room that’s shorter than you.

*Little kids:* Who’s the tallest person in your family? How many feet taller than you is he or she? Find out your height to the closest foot. *Bonus:* If you grow 1/2 inch overnight AND stretch another 1/2 inch, how much taller are you in the morning?

*Big kids:* If you grew 1/2 inch every day, how much could you grow in 1 week? (Hint if needed: How much could you grow in 2 days, then in 4, then in 6…) *Bonus:* If you grow 1/2 inch each month, with your first in this month (November), in what month will you be 3 inches taller?

__Answers:__

*Wee ones:* Answers may include a bedpost, a chair back, or a baseball bat leaning against the wall.

*Little kids:* Different for everyone…find out that person’s height, then subtract your own. *Bonus: *1 inch.

*Big kids:* 3 1/2 inches. *Bonus:* In April, since you need 6 monthly spurts including November.

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]]>The post Trip across the Tridge appeared first on Bedtime Math.

]]>A bridge is a simple idea: stretch a road from one side of a river to another, and people can cross without having to swim. But this bridge takes it one step further. Our friends in Midland, Michigan are home to a three-way bridge, which they call the Tridge. It’s a wooden footbridge (no cars!) that crosses the Chippewa River once and the Tittabawassee River twice. Here we see it from above. The bridge is just 8 feet wide, and each spoke is just 180 feet long from the center to the riverbank, less than 1/20 of a mile. It’s not that far, but definitely easier to walk it than swim.

*Wee ones:* If you drew straight lines to connect the Tridge’s ends to make a 3-sided shape, what shape would that be?

*Little kids:* If you walked on the bridge from the left side, reached the middle and turned right, which part would you then walk on? Point to it. *Bonus:* If you lay across the 8-foot-wide Tridge, how much taller would you need to be to stretch across? Find out your height to the closest foot!

*Big kids:* Look at the cars in the upper right — they look so small! About how many of them look like they could fit end to end from the water’s end to the middle of the Tridge? *Bonus:* How long is 1/10 of a mile? (Reminder if needed: A mile has 5,280 feet.)

*The sky’s the limit:* If you start on the left, cross the bridge to the upper right corner, then cross from there to the bottom right, then cross again to end up at your start, will 10 full trips like that give you a mile of walking?

__Answers:__

*Wee ones:* A triangle.

*Little kids:* The bottom right part. *Bonus:* Different for everyone…subtract your height in feet from 8.

*Big kids:* In reality you could fit about 9 of them. *Bonus:* 528 feet.

*The sky’s the limit: *Yes. You walk 6 of these 180-foot spokes in 1 full trip, or 1,080 feet. So 10 trips will require walking 10,800 feet, which is more than the 5,280 feet in a mile – in fact, it’s more than 2 miles!

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]]>The post Tower of Daredevils appeared first on Bedtime Math.

]]>If you’ve ever tried to carry someone piggyback, you know it’s hard work. Now imagine that friend standing on your shoulders, with 8 other people stacked above both of you! Every year in Spain, people come together to see who can stack up to make the tallest tower, or “castell” — without anyone falling. Each team’s members crowd together, then start stepping on each other’s heads and grabbing each other’s sashes to climb up. Some people have made castells 10 people-layers high! The bottom level is called the “pinya”: their job is to hold everyone up, and catch anyone who falls. If you like heights you can climb to the top; if you don’t, you can stay at the bottom, but be ready to be stepped on.

*Wee ones:* If a tower has 6 layers of people stacked, what number layer is next?

*Little kids:* If you stack a green-shirt person, then blue, then green, then blue, then green, does the tower have more green shirts or blue shirts? *Bonus:* If they stack 9 layers and you’re in the very middle layer, in which layer are you?

*Big kids:* If you’re in a 14-layer tower, and there are 3 more layers below you than above you, in which layer are you? *Bonus:* If everyone in a 10-layer tower is 5 1/2 feet tall, how high is the top of the tippy-top person’s head?

__Answers:__

*Wee ones:* The 7th layer.

*Little kids:* More green shirts. *Bonus:* The 5^{th} layer.

*Big kids:* 5 above you and 8 below, so you’re the 9th layer. You need 2 numbers 3 apart that add to 13 (all the layers minus your own). *Bonus:* 55 feet.

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]]>The post For Those Who Really Love Snakes appeared first on Bedtime Math.

]]>Fishermen get super excited when they catch a big fish. But they usually aren’t expecting one that’s longer than the boat! This photo shows an 18-foot-long oarfish, found off the coast of California by scientist Jasmine Santana. It was dead, but its whole huge body was still hanging together, and it took 15 people to drag it across the beach. These monstrous, snake-like creatures live in very deep waters, from 1,500 to 3,000 feet down. So we don’t see them often. But sometimes when oarfish are sick, they swim up to the surface. These may be the same fish that long-ago people thought were sea monsters. We now know they aren’t monsters, but we probably aren’t looking to keep one as a pet, either.

*Wee ones*: Count to find the 5th person from the right. What color are his shorts?

*Little kids*: If this snake is 18 feet long and the scientist’s boat was 1 foot longer, how long was her boat? *Bonus*: It took 15 people to drag this animal out of the water. But we see 17 people in the photo. How many extra people joined the photo?

*Big kids*: If of the 16 people behind the fish, 4 hands aren’t helping hold it up, how many hands are? *Bonus*: Back in 1808, a crazy-long 56-foot oarfish washed up in Scotland. It was the first oarfish ever found. How many years ago was that as of now (the year 2018)?

*The sky’s the limit*: Who actually helped lug the oarfish from the water, and who just jumped into the picture? There are 9 women and 8 men shown. If the original group of 15 “luggers” had 3 more men than women, but of those, 1 man and 2 women didn’t stay for the picture, how many new people who didn’t help jumped into the photo?

__Answers__:

*Wee ones*: That guy has red shorts.

*Little kids*: 19 feet long. *Bonus*: 2 extra people.

*Big kids*: 28 hands, since 4 out of 32 hands aren’t helping. *Bonus*: 210 years ago.

*The sky’s the limit*: The original group had 3 more men than women, then if 3 of those men had left, it would have been 12 people with an even split (6 men, 6 women). So there were 9 men and 6 women. If 1 man and 2 women left, then 8 real men and 4 real women stayed for this picture. There are actually 8 men and 9 women here, which means 5 women joined the photo.

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]]>The post Stuck Truck appeared first on Bedtime Math.

]]>Next time you drive under a bridge or overpass, look for a sign on the side with numbers on it. It will tell you the bridge’s height above the road in inches and feet. Why? So we don’t have what happened in this picture! This truck tried to drive under a bridge even though it was too tall to fit. So the truck got stuck, and had to be pulled out. One way is to let the air out of the tires so the truck sinks lower and can roll out slowly. So why do trucks get stuck? Maybe the trucks are taller than their drivers think? Maybe the driver just doesn’t believe the sign? Either way, this is a case where doing the math could save the day.

*Wee ones:* Which is taller in that picture, the car on the left or the truck on the right?

*Little kids:* The truck got stuck at 2:00 pm, If it didn’t get un-stuck until 2 hours later, when did the truck finally roll free? *Bonus:* If the truck is an 18-wheeler and you’ve let the air out of just 1 tire, how many tires do you have left to do?

*Big kids:* If the bridge height was 11 feet 11 inches and the truck was 1 inch taller, how tall was the truck? (*Reminder if needed:* How many inches are in 1 foot?) *Bonus:* If that truck had a 36-mile trip, and the distance it had traveled so far was only 1/2 of what it had left, how far had it driven so far?

__Answers:__

*Wee ones:* The truck is taller.

*Little kids:* At 4:00 pm. *Bonus:* 17 wheels.

*Big kids:* 12 feet. *Bonus:* 12 miles. If the distance that’s left is double the distance traveled already, that’s the same as having 3 pieces all that length….and 36 divided by 3 is 12.

The post Stuck Truck appeared first on Bedtime Math.

]]>The post Bug-Sized Book appeared first on Bedtime Math.

]]>There’s something nice about turning the pages of a fresh new book full of pictures. Well, that all feels a little different when the book is barely 1/8 of an inch wide! A couple of years ago, librarians found one of the world’s teeniest books hidden in a college library. As you can see in the photo, it’s about the size of a ladybug. The words are so tiny that you need a magnifying glass to read them. This book happens to be a chapter from the Bible, but the same library has 4,000 other mini-books, too. If you want to stop by for an hour of two of reading, you’d better bring extra-strong glasses.

*Wee ones:* Look at a book in your room. What shape is the cover?

*Little kids:* If you put a mini-book on the tip of each of your fingers but not your thumbs, how many mini-books are you holding? *Bonus:* If instead you fit 10 mini-books in each of your 2 pockets and another 10 under your hat, now how many books are you carrying?

*Big kids:* If you’re taking 100 mini-books off the shelf and can grab 10 at a time, how many handfuls does it take to grab them all? *Bonus:* The teeny book has a “big sister” book, an exact copy that is 1 and 3/8 inches wide. How many teeny books could fit across the big sister book, if the little one is 1/8 inch wide? (Hint if needed: How many of the 1/8-inch books can fit across just 1 inch?)

__Answers:__

*Wee ones:* Most books have a rectangle cover, or if all 4 sides are the same length, it’s square.

*Little kids:* 8 mini-books. *Bonus:* 30 mini-books.

*Big kids:* 10 handfuls. *Bonus:* 11 of them. You can fit 8 of them across that first inch, and then another 3 across the 3/8 inch left.

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]]>The post Pocket Pet appeared first on Bedtime Math.

]]>If you like teddy bears, you might have a koala among your stuffed animal friends. The funny thing is, koalas aren’t bears. These fluffy-eared furballs are “marsupials,” meaning they’re more like kangaroos than bears. They carry their brand new babies in a pouch on their tummy. Baby koalas are even called joeys just like baby kangaroos. Koala joeys start life with almost no fur, and live in that pouch for 26 weeks before even poking out to look around. Finally they climb out and start eating koalas’ favorite food, tree leaves. Climbing those trees must be hard work: even as grown-up furballs, koalas sleep 20 hours a day!

*Wee ones:* Find a piece of clothing with pockets, and count them. How many pockets does it have?

*Little kids:* If a mama koala is carrying 5 joeys, how many koalas is that all together? *Bonus: *Koalas sleep 20 hours a day! Out of a 24-hour day, how much time are they awake?

*Big kids:* 26 weeks is the same as 6 months. If a koala is born in March, in what month does it finally crawl out of mom’s pouch? *Bonus:* A full-grown koala can weigh up to 33 pounds – a heavy furry friend to lug around! How much more (or less) do you weigh?

*The sky’s the limit:* A grown-up koala eats about 2 1/2 pounds of leaves each day. How much does it eat in a 30-day month? (Hint for those new to fractions: how much does it eat in 2 days? And how many 2-day sets are in a month?)

__Answers:__

*Wee ones:* Different for everyone…a pair of pants might have just 2 pockets, or 4, or maybe more!

*Little kids:* 6 koalas. *Bonus:* Just 4 hours.

*Big kids:* In September. *Bonus:* Different for everyone…subtract 33 from your weight in pounds, or subtract your weight from 33 if you’re a little tyke.

*The sky’s the limit:* 75 pounds, since they eat 15 2-day sets of 5 pounds.

The post Pocket Pet appeared first on Bedtime Math.

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