Potato Chips That Rock ‘n Roll

Someone figured out that you can stack Pringles potato chips to make them stand in a full circle! As we see in this video clip, it takes a few tries to make it work. But Pringles are all the same shape — a hyperbolic paraboloid, if you want the exact math name — and every can holds about 100 chips. So you have plenty of chips for stacking — but you’d better eat fast before they roll away!

Wee ones: These chips are stacked in a circle.  Find 3 circle-shaped things in your room.

Little kids: If you stack 4 chips, then eat 2 of those, then stack on 3 more, then eat 2 more, how many chips are left in your stack?  Bonus: If a whole circle of 80 chips rolls off the table and you pick them up in handfuls of 10, what numbers do you say to count them?

Big kids: If you add a chip on the left side, then the right, then the middle, then left again to repeat, where do you stack the 29th chip?  Bonus: If every can of Pringles has 100 chips, after those 29 how many are left to stack?

Answers:
Wee ones: Items might include clocks, rims of cups, mirrors, and toy balls (seen from the side).

Little kids: 3 chips.  Bonus: 10, 20, 30, 40, 50, 60, 70, 80.

Big kids: On the right, since it’s 2 slots past 27, a multiple of 3, and all multiples of 3 land in the middle.  Bonus: 71 chips.

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