Apparently I'm stuck on the fuse puzzle part. I've put the correct fuses into their respected places and it seems that the game doesn't progress any further. This happens on my second play tho. Thanks and keep up the good work!
Well, you must use the sum of these two math problems. Try finding all fuses and power the elevator by using "40+10" and "20-15"
If you are having problems, try using this guide