Have you ever made a milkshake? You dump ice cream in a cup, pour in some milk, and mix it up into a sweet goopy treat. This kind of milkshake has been around only since 1922, when a worker at Walgreens tried mixing ice cream and milk. But now the milkshake has turned fancy in New York City. A burger joint called Black Tap has started topping their shakes with mountains of cotton candy, extra ice cream, chocolate chip cookies, peanut butter cups, and really anything else. It’s like having an ice cream sundae on top of your shake! People wait for up to 2 hours to try one of these tippy treats, which stand up to 1 foot tall. Don’t even try eating a burger first!
Wee ones: If your mega milkshake has milk, ice cream, cookies, whipped cream and chocolate sauce, how many ingredients does it have?
Little kids: If you try a shake every day this week starting on Sunday, but on Saturday you eat 2 shakes instead, how many do you have in total? Bonus: The shakes are not quite a foot tall. If they’re 1 inch shorter than 12 inches, how tall are they?
Big kids: If you get in line at Black Tap at 2:09 pm and wait 1 hour 14 minutes, at what time do you finally get your milkshake? Bonus: There are 3 crazy shakes: Cotton Candy, Sweet and Salty, and Cookie. If Black Tap serves 28 shakes in that repeating order, how many of each kind do they serve?
The sky’s the limit: If today Black Tap serves twice as many Sweet and Salty shakes as Cotton Candy, and 3 times as many Cookie shakes as Sweet and Salty, how many of each shake do they serve if the total is 36?
Answers:
Wee ones: 5 ingredients.
Little kids: 8 shakes. Bonus: 11 inches – still really crazy for a shake!
Big kids: At 3:23 pm. Bonus: 10 Cotton Candy, 9 Sweet/Salty and 9 Cookie.
The sky’s the limit: 4 Cotton Candy, 8 Sweet and Salty, and 24 Cookie. If you have 2 of the SS for every CC, and then 3 times as many Cookie as SS, then you have 6 Cookie ones for every CC and for every 2 SS, making sets of 9 shakes. And you can fit 4 of those sets in 36. (If you want to show with algebra, c + 2c + (3 x 2c) = 36, so 9c = 36 and c = 4).
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.