（3.5+6）*4-3.4 .
=(10-0.5)*4-3.4
=40-2-3.4
=34.6
7.36-（2.36+3.76）
=7.36-2.36-3.76
=5-3.76
=1.24
.28.5*1+2.85*90
=2.85*10+2.85*90
=2.85*100
=285