I prepared a task card to give to my students.
The other thing that students really struggled with was realizing that they couldn't just eyeball "half" of a bucket. One of my students had seen this puzzle before, so her group whizzed right through it.
Here are the posters my groups came up with. I am a bit disappointed with the quality of the posters, but I believe that is my fault because I didn't set out clear expectations for what I wanted. I'm always learning every day.
All of my groups did eventually get there, even if it did take a little prompting from me to get them started.
Files for this activity can be found here.