If you’ve ever tried to carry someone piggyback, you know it’s hard work. Now imagine that friend standing on your shoulders, with 8 other people stacked above both of you! Every year in Spain, people come together to see who can stack up to make the tallest tower, or “castell” — without anyone falling. Each team’s members crowd together, then start stepping on each other’s heads and grabbing each other’s sashes to climb up. Some people have made castells 10 people-layers high! The bottom level is called the “pinya”: their job is to hold everyone up, and catch anyone who falls. If you like heights you can climb to the top; if you don’t, you can stay at the bottom, but be ready to be stepped on.
Wee ones: If a tower has 6 layers of people stacked, what number layer is next?
Little kids: If you stack a green-shirt person, then blue, then green, then blue, then green, does the tower have more green shirts or blue shirts? Bonus: If they stack 9 layers and you’re in the very middle layer, in which layer are you?
Big kids: If you’re in a 14-layer tower, and there are 3 more layers below you than above you, in which layer are you? Bonus: If everyone in a 10-layer tower is 5 1/2 feet tall, how high is the top of the tippy-top person’s head?
Wee ones: The 7th layer.
Little kids: More green shirts. Bonus: The 5th layer.
Big kids: 5 above you and 8 below, so you’re the 9th layer. You need 2 numbers 3 apart that add to 13 (all the layers minus your own). Bonus: 55 feet.
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.