i still dont understand, sorry. So you take the first two numbers and put them through the symbols?
First off, the music sheet is not used here. You're right it's all in the showcase. From the showcase, you take the 4th place in performance & the 2nd place in composition. These two places add to be 6. Which is used, and shown on the music box(on the circle with the + sign). This is the only dial(circle with an icon) given to you. But, that's where the 4 and 2 come into play. You put the dials(the music note and the trophy) at 4 & 2. Then after you are just doing the equation given with these two numbers.
E.g:
Since 4+2=6
What is 4x2=?
Or 4-2=?
Or 4/2=?
Please let me know if this was more helpful! If not, I can try again to re-explain it. :)