It’s Girl Scout cookie time, when Girl Scouts all across America sell boxes of cool Thin Mints, peanut buttery Tagalongs, and coconutty Samoas. In fact, even though Oreos are the most popular cookie most of the year, Girl Scout cookies beat them out from January to March! More than 200 million boxes of GS cookies sell every winter. All the boxes are about the same size, so they can stack neatly in the truck (and on your kitchen table). But there’s a different number of cookies in each type of box. Thin Mints stack up in two long tunnels of plastic wrap, but Samoas sit in a tray so they won’t break. If you want as many Girl Scout cookies as possible, you’ll have to do the math.

*Wee ones:* What different shapes are the cookies you see above?

*Little kids:* What number cookie is the dark brown Thin Mint above, counting from the left? *Bonus:* If you eat 2 of each of the 9 cookies shown, how many do you eat in total?

*Big kids:* If you make 2 stacks of Thin Mints and one has 2 more cookies than the other, and together they have 14 cookies, how many Thin Mints are in each stack? *Bonus:* If one Girl Scout sells 4 boxes, the next girl sells 10 boxes, the next sells 16 boxes, and the next sells 22 boxes…how many boxes does the next girl sell to keep the pattern?

*The sky’s the limit:* If a Girl Scout sells either 8 or 15 boxes of any flavor, what combination of amounts could she sell that comes to exactly 100 boxes total?

Answers:

*Wee ones:* Mostly circles, plus a 4-leaf clover (4th from left) and a hexagon with a hole (3rd from right).

*Little kids:* The 5th cookie. *Bonus:* 18 cookies.

*Big kids:* 8 Thin Mints in one, 6 in the other. If they were even, they’d be 7 and 7. *Bonus:* 28 boxes, since each Scout sells 6 more than the one before.

*The sky’s the limit:* 15 boxes each of 4 flavors (60 boxes), then 8 boxes each of 5 more flavors (40 more boxes).

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.