Students having been learning about inference and Close Reads.  They were reading a story about a boy who had to wriggle through a crack that was 30 feet long and 7.5" wide. Wriggling was a new verb, the author didn't tell them how old/big the boy was,  and they couldn't quite imagine the actual size of the crack, so using their math skills, they created the crack to figure out all three. 

He was definitely not in 3rd grade!