Sure, we oooh and aaah over cute cuddly dogs, kittens and bunnies. But what about cows? Today we celebrate them on National Cow Appreciation Day. Not only do these sweet, wide-eyed animals give us milk, cheese, and ice cream, but they also give us some great math. Cows’ eyes can see almost all the way around in every direction, and their noses can smell things from 5 miles away. Their stomachs have 4 parts to digest all the tough, scratchy grass they eat. Most amazing is the amount of milk they make: About 110,000 farms in the U.S. milk a total of 9 million cows, and the best cows make up to 25 gallons a day! So next time you drink a glass of milk, say thank-you to our furry farm friends.
Wee ones: If you count 3 cows coming down the street, then see 1 more, what number is that cow?
Little kids: If you and your pet cow go for a walk, how many legs do you have together? Bonus: If you’re counting off the 25 gallons milked from a cow, what are the last 3 numbers you say?
Big kids: If 9 million cows each make 10 gallons of milk a day on average, how many gallons do they make all together in one day? Bonus: If a crowd of people and cows hangs out on a hill, and there are twice as many cows as people and 50 legs in total, how many of each mammal are there? (Hint if needed: If you put them in small equal groups, how many total legs would that group have?)
Wee ones: Cow #4.
Little kids: 6 legs. Bonus: 23, 24, 25.
Big kids: 90 million. Bonus: 5 people and 10 cows. If there are twice as many cows as people, then each person has 2 cows with him, and each of those sets has 10 legs. For 50 legs total, there must be 5 groups like that.
Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.