How does a vacuum cleaner work? The machine has a really strong fan spinning inside. Instead of blowing air out at you, the fan pulls air — and dirt, and Lego, and little fuzzies from your sweater — up into the vacuum. A normal vacuum cleaner can lift about 5 pounds with the hose attachment, and can suck up about 12 gallons of milk every second, so that’s a lot of cleaning up!
Wee ones: Vacuum cleaners suck up tiny bits of things. Find 3 things in the room that are smaller than the tip of your finger.
Little kids: If the vacuum sucks up 5 Lego bricks and a sock, how many things has it eaten? Bonus: If the vacuum eats up 8 chocolate chips from the kitchen floor, how do you count down the chips from 8 to 1? Try it!
Big kids: All the junk sucked up by a vacuum has to be emptied out. If you do this every 3rd day starting on a Sunday, on what number cleaning do you empty it on a Thursday? Bonus: If on every 4th emptying you find a Cheerio and on every 5th emptying you find a penny, what’s the 1st emptying when you find both? (Assume you count every 4th emptying starting with the 4th, and every 5th emptying starting with the 5th).
Answers:
Wee ones: Items might include a button, a marble, or an eraser that’s snapped off a pencil.
Little kids: 6 things. Bonus: 8, 7, 6, 5, 4, 3, 2, 1.
Big kids: The 7th cleaning. The 8th will be on a Sunday just like the 1st, and you start the pattern over again! Bonus: The 20th emptying.
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.