The post Flowers That Count appeared first on Bedtime Math.

]]>Spring is here, and that means our friends the flowers are just around the corner. What’s cool is that some flowers do math without even knowing it! Sunflowers always have a certain numbers of petals — only some numbers can work. There’s a special set of numbers where you get each number by adding the 2 numbers before it. You start with 1 and 1, which gives you 2…then 2+1 is 3…then 3 plus that 2 gives you 5…5 plus that 3 gives 8, and so on. They’re called the Fibonacci numbers, and sunflowers always have a Fibonacci number of petals! Let’s see how big that flower can get.

*Wee ones:* If the first few Fibonacci numbers are 1, 2, 3 and 5, which number did we skip that we would have said if counting?

*Little kids:* If the last 2 Fibonacci numbers we got were 5 and 8, what’s the next number? (Reminder: You get each number by adding the previous two numbers.) *Bonus:* If you have a flower with that many petals and another with 5 petals, how many do they have together?

*Big kids:* Can a sunflower have 25 petals? *Bonus:* For fun we also have “Tribonacci” numbers, where you add the last 3 numbers to get the next. Since it also starts with 1, 1, and 2, what are the next 3 Tribonacci numbers? See if you can remember all the pieces in your head!

Answers:

*Wee ones:* 4.

*Little kids:* 13. *Bonus:* 18 petals (13 + 5).

*Big kids:* No, because after 21 we add 21 + 13, which is 34. *Bonus:* 4, 7, and 13.

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]]>The post Egg Hunt appeared first on Bedtime Math.

]]>*(Note to parents: As we do on special holidays, today we’ve included an extra math problem about Easter, for those who celebrate or would like to learn more about the day. Enjoy!)*

Today is Easter Sunday, the day that Christians celebrate the rising of Jesus from the dead. On this holiday we also mix in a lot of fun, playful stuff, like fluffy chicks and Easter bunnies carrying eggs. But even that egg is very serious and special. It’s a symbol of the empty stone tomb of Jesus: an egg is round and smooth like a stone, but life comes out of it. Others say it’s like the stone rolled away to open His tomb. For centuries people didn’t eat eggs during the 40 days of Lent for that reason, and some people still follow that rule. So it’s no surprise that people started Easter egg hunts to celebrate Easter at the end of Lent. Best of all, the eggs you find sometimes have candy inside them — and as we see here, the treats can add up fast.

*Wee ones:* If you find a blue egg, then a yellow, then a green, then back to blue, then yellow…what color do you think you find next?

*Little kids:* If you find a blue egg, then a yellow, then a green, then back to blue to repeat, what color is the 8th egg? *Bonus:* If each of the 8 eggs has 2 candies inside, how many candies in total did you get?

*Big kids:* If the Easter Bunny hides 4 purple eggs, twice as many pinks as purples, and 3 times as many blues as pinks, how many eggs is that all together? *Bonus:* If 1/2 the eggs have a jelly bean and a chocolate egg inside, while the other half have 2 jelly beans, how many jelly beans are hidden in the eggs?

*The sky’s the limit:* The Easter Bunny has to keep secret how many eggs he hid. But he can tell you that if you multiply that number by itself, add 9, and then subtract 2, you get 56. How many eggs did the Easter bunny hide?

Answers:

*Wee ones:* Green.

*Little kids: *Yellow.* Bonus: *16 candies.

*Big kids:* 36 eggs, since you have 4 purple, 8 pink and 24 blue. *Bonus:* 54 jelly beans!

*The sky’s the limit:* 7 eggs.

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]]>The post Rainbow Sheep appeared first on Bedtime Math.

]]>When we think of sheep, we usually think of fluffy white sheep, or maybe black ones from the song “Baa Baa Black Sheep”…or maybe just brown, dirty, smelly sheep. We definitely don’t think of pink sheep or green sheep. So we’ve always loved this photo of rainbow sheep from Scotland; they say the farmer dyed his sheep different colors, from blue to yellow to purple. The sheep don’t seem to care, and when he shears their wool, the sweaters he makes will already look beautiful!

*Wee ones:* Some of these crazy sheep are green. Try to find 3 green things in your room.

*Little kids:* If the farmer dyed 3 sheep pink and 7 sheep purple, how many eye-catching sheep is that? *Bonus:* If he then dyed that same total number of sheep blue, now how many colored sheep does he have?

*Big kids:* If the farmer dyes 6 sheep green, how many green sweaters will they make at 8 sweaters per sheep? *Bonus:* If the farmer wants 61 blue sweaters, how many sheep does he need to dye blue to have enough blue wool?

*The sky’s the limit:* If you have sheep in 5 colors — pink, purple, green, blue and yellow — and you’re making striped sweaters with any 3 different colors of stripes, how many different color combos can you make? (Don’t worry about the order, just the trios of colors.)

Answers:

*Wee ones:* Items might include shirts, socks, tennis balls, plants, or leaves from outside.

*Little kids:* 10 sheep. *Bonus:* 20 sheep.

*Big kids:* 48 sweaters. *Bonus:* 8 sheep, since 7 sheep will give him only 56 sweaters.

*The sky’s the limit:* 10 trios of colors. This is a 5-choose 3 math problem, which is the same as a 5-choose-2, because it’s like picking the two colors you WON’T use in each sweater. You can leave out the pink and either purple, green, blue, or yellow, giving 4 choices; you can leave out the purple with green, blue or yellow, since you already counted pink + purple; that gives you 3 more. And so on until you get 4+3+2+1 = 10.

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]]>The post Spoons with Style appeared first on Bedtime Math.

]]>When you see what cool things people can make out of plain old plastic spoons, you might never throw out a spoon again. On one site, an artist cut the handles off 125 plastic spoons, painted the scoop parts yellow, then glued them onto a clear plastic bottle with a light bulb inside. That makes a lamp that looks like a pineapple. On another page, someone else glued together spoon scoops to make a flower clock. The 250 pieces fan out to make an 18-inch-wide flower face. Now we can decorate our houses while saving some trash from the dump, too.

*Wee ones:* On the flower clock, which row uses more spoons, a circular ring near the middle or a ring near the outer edge?

*Little kids:* If the pineapple lamp uses 5 spoons in the top row and 1 more than that in the next, how many does it use in that 2nd row? *Bonus:* How many does it use in both rows together?

*Big kids:* If the flower clock uses 22 spoons in the center ring, and each new ring uses 3 more than the one inside it, can a ring have 34 spoons in it? *Bonus:* If the pineapple uses 100 spoons, with 8 spoons in as many rows as possible, how many full rows of 8 does it have?

Answers:

Wee ones: The ring near the outside.

*Little kids:* 6 spoons. *Bonus:* 11 spoons, since it’s 5 + 6.

*Big kids:* Yes! There will be 25, 28, 31, and 34 spoons in the next 4 rows. *Bonus:* 12 rows, which brings us to 96 spoons plus 4 left in the last row.

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]]>The post The Story of Passover, Rube Goldberg-Style appeared first on Bedtime Math.

]]>We bet you’ve never seen the story of Passover told like this. Passover, which starts tonight, is the Jewish celebration of freedom from slavery in Egypt over 3,000 years ago, and the creation of the Jewish nation under Moses. To help everyone understand the story behind the holiday, these students built a Rube Goldberg machine that shows it all. In a Rube Goldberg machine, each piece falls, tips or rolls to knock another piece, which knocks another piece, causing all kinds of crazy things to happen. As you see in this video, each set of stunts tells a story from the Torah, from a fan blowing a baby doll across a kiddie pool (Moses in the river) to branches catching on fire (the Burning Bush). See if you can count the pieces, and tell the story yourself!

*Wee ones:* If the machine shows the Plague of Blood, the Plague of Frogs, the Plague of Hail and the Plague of Darkness, how many plagues is that? (Don’t worry — they use red food dye and Dominoes for that first one.)

*Little kids:* If the dominoes take 2 seconds to turn off the lights for the Plague of Darkness, and the lights stay off for 8 seconds, how long did that story take? *Bonus:* If the lights go off at 1 minute 25 seconds into the video, at what time do they flick back on 8 seconds later?

*Big kids:* If the machine has 10 domino runs with each using 20 blocks or pieces of matzo, how many pieces in total had to be set up? *Bonus:* If each tipping piece of matzo is 1/2 inch taller than the piece before it, how tall is the 9th piece if the 1st one was 5 inches tall?

Answers:

*Wee ones:* 4 plagues.

*Little kids:* 10 seconds (8 + 2). *Bonus:* At 1 minute 33 seconds.

*Big kids:* 200 pieces. *Bonus:* 9 inches tall, since the 8 jumps will add 4 inches total.

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]]>The post An Out-of-this-World Workout appeared first on Bedtime Math.

]]>The Moon looks kind of small in the night sky, doesn’t it? But it’s a pretty big place! Its circumference, or distance all the way around at the widest point, is 6,786 miles. That’s more than 2 times the distance across the U.S. So our friend Penelope B. wondered, how long would it take to walk around the Moon? Thanks to astronauts, we know that the fastest you can walk on the moon is just over 3 miles per hour – any faster than that and you’ll break into a bouncy run. That means 2,184 hours of walking. If you want to catch 8 hours of sleep each night, it would take you exactly 136 1/2 days to walk all the way around. But what if you could walk nonstop – how fast could you do it? Let’s find out!

*Wee ones:* A full moon looks like a circle in the sky. Find 4 circle shapes in the room.

*Little kids:* How many miles would an astronaut walking 3 miles each hour travel in 2 hours? *Bonus:* If one astronaut takes 6 bouncy steps, another takes 10 steps, and a third takes the number exactly halfway between those two, how many steps does the third astronaut take?

*Big kids: *What fraction of a 24-hour day is 8 hours of sleep? *Bonus:* If you walk 24 hours a day every day, how many days does it take to walk the 2,184 hours to go around the Moon? *Hint:* To divide by 24, you can figure out what small numbers multiply out to make 24, then divide by each of those one at a time to get your answer!

Answers:

*Wee ones: *Possible items include plates, rims of cups, clocks, buttons, and doorknobs..

*Little kids: *6 miles, because 3 + 3 = 6. *Bonus: *8 steps, since that’s 2 steps from 6 and from 10.

*Big kids: *8 hours out of 24 is 1/3. *Bonus: *91 days, or about 3 months. 24 is 2 x 2 x 2 x 3, so you can cut 2,184 hours in half three times in a row, then divide by 3 to get your answer: 2,184 –> 1,092 –> 546 –> 273, then divide by 3 to get 91.

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]]>The post A Better Kind of “Square Dance” appeared first on Bedtime Math.

]]>We are loving this wild video sent by our fan Catherine M. Two guys named Sadeck and Ammar do a hip-hop-like dance — but it all involves making shapes. They snap their arms into squares, diamonds, Xs and other forms, all to the beat of the music. See how many shapes you can spot!

*Wee ones:* What shape are they making here? Count the sides!

*Little kids:* Find a grown-up or another family member, and make a square together with your arms. See how fast you can do it! *Bonus:* How many fingers do those 2 guys have together?

*Big kids:* If Sadeck and Ammar make a big square, then an L, then a little square, then an X, then a big square again to repeat the pattern, what’s the 18th shape? *Bonus:* What’s the 118th shape? See if you can get it without counting all the way up.

Answers:

*Wee ones:* A square, which has 4 sides.

*Little kids:* Make a square with your arms and someone else’s! *Bonus:* 20 fingers.

*Big kids:* An L. Every multiple of 4 is the last shape (an X), and 18 is 2 shapes past that. *Bonus:* Also an L. 100 is a multiple of 4, so you start over just as with 1. So 118 will be the same as 18.

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]]>The post Return of the Super-Sized Stingray appeared first on Bedtime Math.

]]>Life as a fish can’t be very exciting, except when some other animal tries to catch you. Well, this stingray has been caught twice by fishermen, and broke a world record both times! Stingrays are very flat, wavy fish with a spike in the back to scare off attackers. Fishermen in Thailand caught a huge stingray that was 8 feet wide — on its side it would stretch from your bedroom floor to the ceiling! It was 14 feet long and weighed between 700 and 800 pounds, making it the world’s biggest stingray. The crazy part is that this same stingray was also caught in 2009, when it was just 6 ½ feet across but 15 feet long (its stinger had broken since). Clearly this fish just likes to show off for us.

*Wee ones:* A stingray is almost shaped like a circle. Find 4 circle-shaped things in your room.

*Little kids:* If the stingray was 6 feet long last time and 8 feet long this time, what counting number did we miss in between? *Bonus:* If you lay facing forward on that 14-foot stingray to ride it, how much longer than you would it be? (You can round your height to the nearest foot.)

*Big kids:* If the stingray grew from 6 1/2 feet wide to 8 feet wide, how many feet did it grow? *Bonus:* If you line up a bunch of 14-foot-long stingrays end to end, how few 6-foot-tall people can line up end to end to match exactly a whole number of stingrays? What’s the smallest number that works?

Answers:

*Wee ones:* Items might include buttons, smiley faces, and the letter O on a book cover.

*Little kids:* 7. *Bonus:* Different for everyone…subtract your height from 14.

*Big kids:* 1 1/2 feet. *Bonus:* 7 people. They will stretch 42 feet long, which equals 3 stingrays. 42 is the smallest common product of 14 and 6…both numbers are divisible by 2, so you don’t need to do 14 x 6. 14 x 3 will give you a number that can be divided by both.

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]]>The post Car Wash of Doom appeared first on Bedtime Math.

]]>Today we have another Math Movie Monday, for Math Awareness Month! Today we see our friend Kevin take a job at the Car Wash of Doom. As you’d guess from the name, just about everything goes wrong at this car wash — and it would all go better if Kevin could do the math. Regular car washes do a pretty good job: there are more than 110,000 car washes in the US, and together they wash 8 million cars a day! Hopefully they do a better job than our friend here — watch to find out why!

*Wee ones:* Car washes use water. Run your sink faucet while you count to 10, then turn it off. Is the sink a little full, halfway full, or totally full? Try it again at a different speed!

*Little kids:* If Kevin’s power washer knocks off 2 front tires and 1 back tire, how many tires does he knock off? *Bonus:* If 8 fish come out of the hose and all but 3 of them squirt into the car, how many fish land in the car?

*Big kids:* Many car washes close during freezing weather. If your car wash runs from the start of March to the end of November, during how many months is it open? *Bonus:* If America washes 8 million cars a day, how many days would it take to wash a car for every one of our 320 million people? (Hint if needed: How many days would it take to wash 32 million cars? and then how does the answer differ?)

Answers:

*Wee ones:* Different for everyone…see how fast your tub fills!

*Little kids:* 3 tires. *Bonus:* 5 fish.

*Big kids: *9 months. *Bonus:* 40 days. It would take 4 days to wash 32 million cars, then you need 10 times as long for 10 times as many cars.

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]]>The post A Prime Time to Rhyme appeared first on Bedtime Math.

]]>April is Poetry Month, and while poetry is made of words, numbers rule their rhyming. Think about Dr. Seuss books, where two lines in a row rhyme: “Knox in box / Fox in socks.” Since the first 2 lines rhyme, then the 3rd and 4th rhyme, we call that an a-a-b-b pattern. But sometimes not all the lines rhyme: “I do not like them, / Sam-I-am. / I do not like / green eggs and ham.” The 3^{rd} line ends in a different sound from the 1^{st} line, so that pattern is a-b-c-b.

It’s hard work, so we were amazed by New Orleans “sidewalk poet” Antoine: Tell him your favorite thing, and he’ll write a poem about it — then you decide how much to pay him for it. We of course asked for a poem about math, which you can find below!

*Wee ones:* If you say “big wig pig,” how many rhyming words do you have?

*Little kids:* Try to think of 4 words that rhyme with your first name. Then say the whole set 5 times fast! *Bonus:* If Antoine writes a $10 poem for your name, and you have $2, how many more dollars do you need to pay him?

*Big kids:* If Antoine thinks up 7 3-letter rhyming words, how many letters does he have to type in total? *Bonus:* Poems called “sonnets” have 14 lines, while “haikus” have just 3. On which day does Antoine type more lines, a 10-sonnet day or a 20-haiku day?

Answers:

*Wee ones:* 3 rhyming words.

*Little kids:* Different for everyone…see if you can rhyme with your name! *Bonus:* $8 more.

*Big kids:* 21 letters. *Bonus:* The sonnet day is more line-heavy: 140 lines v. 60 lines.

And here is Antoine’s poem – thank you Antoine for the inspiration!

it’s a system

click

it’s a system of an infinite

number of systems

it’s the imagination

at play

inventing dimensions

into dimensions

turning an equation into

a sculpted crystal

floating somewhere

around which

the mind circles

admiring

it’s the art

of creating sideways

back alleys

and getting stuck into

nerve-wracking dead-ends

and try again

and again

till it equals

true.

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