11. Insert the four operation symbols $+,-, x, \div$ into the $O$ in the following equation to make the equation true (each operation symbol can only be used once):
$$
(132 \bigcirc 7 \bigcirc 6) \bigcirc(12 \bigcirc 3)=6
$$
Reference answer: $-, x, \div, +$
Key point: Number puzzles - horizontal number puzzles