Arkansas is a pretty surprising state. First of all, the name doesn’t sound a lot like how it’s spelled. Secondly, there are diamonds in the ground – and you can grab them almost for free! That’s right, Arkansas is home to Crater of Diamonds State Park. This place used to be a diamond mine, but now it’s open to everyone. Kids under 6 years old can search the field for free and older kids have to pay just $6. Visitors have found more than 33,000 diamonds since the park was opened in 1972. One person even found a colorless, flawless stone (no chips or scratches). That’s a 1-in-a-billion rock! The 3 largest diamonds found in America all came from Arkansas. This is the state that really shines.
Wee ones: If kids have to pay 6 dollars to search for diamonds and grown-ups have to pay 8 dollars, who pays more?
Little kids: If there are 2 diamonds found each day at Crater of Diamonds, how many will be found during 1 week? Bonus: The largest diamond ever found at Crater of Diamonds – and in America – weighed 40 carats (a tiny amount of weight). The 2nd-largest found there weighed 34 carats. How much more did the largest weigh? Count up from 34 if it helps!
Big kids: If visitors find 600 diamonds in a year, how much does each one have to be worth to total more than $2000, if they all can sell for the same price? Bonus: If you visit the park every day starting on a Sunday and find a diamond every 3rd day starting that day, how long until you find one on a Thursday? What’s a shortcut to figure this out?
The sky’s the limit: There are so many diamonds at Crater of Diamonds because old mining machines had bigger mesh screens, and anything smaller than 1/16th of an inch fell through. How many 1/16th-inch-wide diamonds would you have to line up to stretch 1 foot in total?
Wee ones: The grown-ups, because 8 is more than 6.
Little kids: 14 diamonds, because 2+2+2+2+2+2+2=14. Bonus: 6 more carats. You can count up: 35 is 1 more than 34, then 36, 37, 38, 39, 40.
Big kids: Just $4 each. $3 each brings the total to $1800, which isn’t quite enough. Bonus: 18 days later. Thursday is always 3 days before a Sunday, and the next Sunday is 21 days later, so we just back up 3 days on the calendar.
The sky’s the limit: 192 diamonds, because there are 16 diamonds in 1 inch, and 12 inches in 1 foot. 16 x 12 = 192. You can make this multiplication easier by breaking the 12 into 10 + 2. 16 x 12 = 16 x 10 + 16 x 2, which = 160 + 32 = 192.
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.