When you drive a car, you can’t just drive as fast as you want. Every road has a “speed limit,” which tells you how many miles an hour you can drive at most. Not everyone follows the rules, though, so police give out speeding tickets: you have to pay money as your punishment. So who got the first speeding ticket ever? That guy was Walter Arnold, back in 1896. He was driving only 8 miles per hour, but in 1896 cars were very new and no one really knew how to drive. So people drove really badly and kept crashing. That’s why the speed limit was only 2 mph – to keep everyone safe. Grown-ups even walk faster than 2 mph, but that was the rule. 3 years later, a taxi driver in New York City was arrested for speeding at 12 mph. Thankfully we’re allowed to drive much faster today, but somehow we still get speeding tickets.
Wee ones: If the speed limit is 8 miles an hour and you’re driving 7 miles an hour, are you driving too fast?
Little kids: If Walter Arnold was going 8 mph in a 2-mph zone, how many miles per hour was he over the speed limit? Bonus: If your street has a limit of 20 miles per hour, and the nearest busy street is 10 more than that, what is busy street limit?
Big kids: If you drive 20 miles an hour, how far can you drive in 4 hours? Bonus: If your family is driving to the beach 180 miles away, and the speed limit is 65 miles per hour, can you get there in 3 hours without breaking the limit? (Hint if needed: How fast would you have to drive to get there in time?)
The sky’s the limit: If a firetruck is zooming at 70 miles an hour, while some slow person is driving only 26 miles an hour, and your speed is halfway between, how fast are you driving?
Wee ones: No, you’re good! 7 is less than 8.
Little kids: 6 miles per hour. Bonus: 30 mph.
Big kids: 80 miles. Bonus: Yes! You can get there by driving 60 miles per hour.
The sky’s the limit: At 48 miles an hour. 26 and 70 are 44 mph apart, so the halfway point is 22 from either of them.
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.