5.66*7.28-3.16*3.16-3.16*4.12
=5.66*7.28-3.16（3.16+4.12）
=5.66x7.28-7.28x3.16
=7.28x(5.66-3.16)
=7.28x2.5
=1.82x4x2.5
=18.2