Water You Doing? - Fay With Your Math (#2)

In case you missed my previous post, I am putting together problems for students at my school to solve outside of math class that I have branded Fay With Your Math. I am trying to find problems that have a low access point and high ceilings, so that everyone from 3rd to 6th graders can try to solve them.

This problem will be the second of the year, so I am still being extra-careful to ensure that the problems are very accessible to the 3rd graders. I lifted this puzzle from the third Die Hard movie (the one with a vengeance).

This problem is very well known and there is a risk that students will be able to google the answer. Still, I like it too much not to use it. Here is the take-home card I made along with a 2-per-page PDF printable. As always, feel free to use this as is or modified. But, let me know if you do. It motivates me to share more. Comment or hit me up on twitter (@mathfireworks)


  • This problem is fun! It has that feeling of impossibility at first, then you tinker around with it, and finally you get that AHA! moment
  • It is easy to understand
  • It can be tried physically with manipulatives
  • Explaining your strategy can be MORE challenging than actually answering the question


While this problem has a low entry level, it does not have a very high ceiling. You sort of either solve it or you do not.

There are ways to extend it: looking for more solutions, finding the most efficient or most precise strategy, or considering jugs of different quantities. However, unless those questions are specifically asked, I am not sure students will explore like I would hope. It will be interested to see. I will report back here once I give the problem to the kiddos.