Brainsnag Level 21 answer: Balance the Scale
The level says: “Balance the scale”
Hints first (no spoilers)
Hint 14 + 3 + 6 is 13. No combination of these makes 12.
Hint 2Numbers can change if you look at them differently. Turn one over.
Hint 3Rotate the 6 crate upside down so it becomes a 9, then put 9 + 3 on the right side.
Show the full solution
4, 3 and 6 cannot make 12. Rotate the "6" crate 180° (two fingers, or scroll the wheel over it on desktop) and it becomes a "9". Put the 9 and the 3 on the right pan: 9 + 3 = 12 and the scale balances.