Allow your students to reveal the hidden picture by matching the equations to the side with the boxes containing their corresponding answer. But beware, for they should also take note that they should follow a certain operational order when performing their calculations; otherwise, they would not be able to match the boxes correctly!
There are a number of ways to convert this into a team game. The teacher can opt to time each group to see how long it would take for them to reveal the mystery picture – the group with the fastest time wins. Alternatively, each group could be given a set time to reveal as many hidden pictures as they can, with the team revealing the most winning the game. Another possible option is that the groups could take turns in revealing a box and then attempting to guess what is hidden underneath; the group that makes the first correct guess wins.