This puzzle is designed for students who have just finished learning how to find the volume of cubes and rectangular prisms. I use this in my combined 6th/7th math class. This is followed well by the Volume of Cylinders Jigsaw.
I start the class period by handing each student a paper-clipped pile of puzzle pieces that I have already cut out. Then they proceed to use the class period and time at home, if necessary, to piece together and tape down the final solved puzzle. Some of the answers are repeated, so they have to find the right answer and the placement that works to make a square with all 9 pieces.