11+2×[3+(4+5×6):2]:5-7=
=11+2×[3+(4+30):2]:5-7=
=11+2×(3+34:2):5-7=
=11+2×(3+17):5-7=
=11+2×20:5-7=
=11+40:5-7=
=11+8-7=
=19-7=12