Fine motor and maths activity. Children have to do the sum, or, for younger children, count the dots, and then match the key up to the correct padlock to open it. This activity not only improves their maths, but also strengthens the muscles in their hands and fingers, which is important for improving writing skills.
This classroom is set up amazingly well. You can see that it is themed, without being frumpy. It is cohesive, yet divided. Each area has its own space. You can easily see that the music area is just the music area. A well set up classroom will have minimal open space to discourage running/rough/'outside' play. Kudoos to this set up!