People vs. Horses appeared first on Bedtime Math.

]]>Can you run faster than a horse? Not if the horse is running its fastest. But you might be able to run fast for longer than a horse. And that’s why the Man vs. Horse race started. The world-record horse speed is 44 miles per hour for a quarter mile, while the fastest running by a human is about 27 miles per hour (by Olympian sprinter Usain Bolt). But in 1980 a guy in Wales named Gordon Green argued that people can outrun horses over a big distance, since a horse can’t keep up its top speed for very long. He and his friends made the race just a little shorter than a 22-mile marathon, and they’ve held the race every year since, with dozens of people and horses competing. Twice a person has actually won: Huw Lobb beat the fastest horse in 2004, and Florian Holzinger won in 2007. They also let people race against the horses on bikes, and in 1989 a British cyclist did win. What we do know is that at the end of it, both the people and the horses need lots of water and a good nap.

*Wee ones:* Who has more legs, a man or a horse?

*Little kids:* When 1 person and 1 horse race, how many running legs do they have together? *Bonus:* If the human gets too tired and stops just 1 mile from the end of the 22 miles, how many miles did he run?

*Big kids:* If horses have a top speed of 44 miles per hour and humans can run 27 miles per hour, how much faster can horses run than people? *Bonus:* 2004 had the most people and animals running: exactly 500 people and 40 horses. How many legs did they have altogether?

*The sky’s the limit:* If the fastest horse runs the first 20 miles at a speed 1/4 *faster* than the fastest person, and reaches the 20-mile mark 30 minutes sooner, at what average speeds did the fastest horse and person each run?

Answers:

*Wee ones:* A horse, which has 4 legs vs. 2.

*Little kids:* 6 legs. *Bonus:* 21 miles.

*Big kids:* 17 miles per hour faster. *Bonus:* 1,160 legs: 1,000 on the people, 160 on the horses.

*The sky’s the limit:* If the horse ran at 5/4 the speed of the runner, then its time would be 4/5 of the runner’s time. So the leftover 30 minutes is the last 1/5 of the runner’s time. The runner ran the 20 miles in 2 1/2, or 5/2 hours, and the horse ran it in 2 hours. Speed x time = distance, so to get the horse’s speed h and the person’s speed p,

2 h = 20 and 5/2 p = 20

h = 10 5 p = 40 so p = 8

So the horse ran 10 miles per hour and the person ran 8 miles per hour.

The post People vs. Horses appeared first on Bedtime Math.

]]>The post When Money Weighs You Down appeared first on Bedtime Math.

]]>*Wee ones:* A U.S. dime is worth 10 cents, and a quarter is worth 25 cents. Which coin is worth more?

*Little kids:* A dime is 10 cents, and a dollar is 100 cents. How many dimes do you need to make a dollar? *Bonus:* If you also have a dollar of quarters, how many coins do you have in total? (Hint if needed: Why is a quarter called a “quarter”?)

*Big kids:* If you have 10 quarters and your friend has 30 dimes, whose pile of coins weighs more? *Bonus:* If you want $9.40 of vending-machine treats and need the most dimes and quarters possible in equal weights, how many nickels will you need to fill in the rest?

Answers:

*Wee ones:* The quarter.

*Little kids:* 10 dimes. *Bonus:* 14 coins: 10 dimes and 4 quarters.

*Big kids:* Your friend’s, since he has $3.00 and that equals the weight of 12 quarters, of which you have only 10. *Bonus:* 8 nickels. If you could do all dimes and quarters, you’d need $4.70 of each, which isn’t divisible by 25 cents. So you’ll need $4.50 of quarters and $4.50 of dimes, leaving you 40 cents short.

The post When Money Weighs You Down appeared first on Bedtime Math.

]]>The post Nuts about Math appeared first on Bedtime Math.

]]>A few years ago, I came across an easy acorn craft that I thought would be perfect for my preschooler. There was only one problem: I lived in a neighborhood with very few mature trees. Try as I might, I couldn’t find an acorn to save my life. Today we live in a different house, and our backyard contains one of the mightiest oaks I’ve ever seen. It’s huge! I laugh to think of that fall when I searched high and low for a handful of acorns. Now I can find a hundred on my back deck.

You might dismiss the acorn as a simple squirrel snack. However, if you can manage to squirrel a few away, you’ll find yourself with a basket full of natural math material.

The gathering of acorns is half the fun. I love escaping from our phones and screens to spend time in nature with my kids. Grab a small basket and announce that you’re going on a family acorn hunt. There are lots of ways to measure how you’ll fill the basket. You can work on fractions – “Tell me when the basket is half full.” Or you can work on counting – “Can you find 10 acorns for me?” Ask them gather all kinds of acorns. The big ones, little ones, ones with caps, and ones without caps.

Pick out a few of the “hat-less” acorns for a fun game. The only other supplies you’ll need are a few wooden matchsticks and a nail about the same diameter as the matchstick. Push or gently pound the nail in to make a hole for the matchstick.

*Ta-dah*! Now you’ve made your own acorn spinning tops!

Practice spinning the tops. Try these challenges once your crew has mastered spinning:

- Whose acorn can spin the longest?
- How many acorn tops can you get spinning simultaneously?
- Is it easier to spin the tops clockwise or counterclockwise?
- Make one of these spinning top game boards and see who can get the most points.

At one time Native Americans used acorns for food, jewelry, and even medicine to calm upset stomachs. Acorns can be dried and stored for many years, and ground into flour for cooking and baking. Much like you’re doing today, Native American children made acorn tops and used them to play games.

I left our basket of acorns on the table for a day, along with a tray, a few bowls, and a kitchen scale. This turned out to be a perfect station for a variety of sorting, measuring and weighing activities.

My kids sorted the acorns by size as well as other defining characteristics, like whether or not they had caps.

They also divided the acorns into two bowls and tried get each bowl to weigh exactly the same amount. It was interesting to then count the number of acorns in each bowl. See for yourself if equal weight indicates the same number of acorns per bowl.

*If all this nutty fun has made you hungry, whip up some of these sweet autumn acorn treats from the Bedtime Math blog. After that, get crackin’ on this acorn-themed Bedtime Math problem.*

*Images courtesy of Angie Six*

The post Nuts about Math appeared first on Bedtime Math.

]]>The post Who Is Man’s Best BFF? appeared first on Bedtime Math.

]]>*Wee ones:* Poodles are now the #8 most popular dog. How many breeds rank higher than they do?

*Little kids:* If you and your black Lab take a walk, how many legs do you have together? *Bonus:* If you have 1 dog of each of the top 5 breeds, how many paws do they have all together?

*Big kids:* In the UK, Cocker Spaniels and Springer Spaniels are ranked #2 and #3, but even added together they don’t match the labs: 34,259 Spaniels vs. 35,026 Labs as of 2013. How many more labs than spaniels were there that year? *Bonus:* In the US there are about 36 registered labs for every 1 million people. When the US had exactly 300 million people, about how many dogs did the US have?

*The sky’s the limit:* The top 3 dog breeds are Labs, Shepherds and Retrievers. If the labs and shepherds add up to 17,000 dogs total, the shepherds and retrievers have 13,000 total, and the labs and retrievers have 16,000 total, how many dogs of each type are there?

Answers:

*Wee ones:* 7 breeds of dogs.

*Little kids:* 6 legs. *Bonus:* 20 paws.

*Big kids:* 767 more Labs. *Bonus:* 10,800 dogs.

*The sky’s the limit:* 10,000 Labs, 7,000 Shepherds and 6,000 Retrievers. You can solve this with algebra, and just work in thousands to make things easier:

l + s = 17

s + r = 13

l + r = 16 so r = 16 – l

Substituting that last one into the 2nd equation, we get

s + (16 – l) = 13

s + 16 – 13 – l = 0

s + 3 = l

Substituting *that* into the 1st equation, we get

s + 3 + s = 17

2s + 3 = 17

2s = 14

s = 7

So there are 7,000 Shepherds. To bring the Lab/Shepherd total to 17, that gives us 10,000 Labs, and to bring the Shepherd/Retriever total to 13, that gives us 6,000 Retrievers.

The post Who Is Man’s Best BFF? appeared first on Bedtime Math.

]]>*Wee ones:* If you counted the minutes as Ahmed swam down, what numbers would you say to get to 12?

*Little kids:* Ahmed trained extra hard for 4 years for this big moment. In what year did he start training? (Reminder: We’re in 2014 right now.) *Bonus:* Ahmed is 41 years old. How old was he when he started training?

*Big kids:* Ahmed’s amazing dive broke the earlier record of 1,044 ft. How much deeper did Ahmed’s 1,090 foot dive go? *Bonus:* How many times as long was his 15-hour trip back up to the surface compared to his 12-minute dive down? (Reminder: An hour has 60 minutes.)

Answers:

*Wee ones:* 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12.

*Little kids:* In 2010. *Bonus:* 37 years old.

*Big kids:* 46 feet deeper. *Bonus:* 75 times as long, since each hour has 5 12-minute chunks.

The post Deep Dive appeared first on Bedtime Math.

]]>