一.45*2.08+1.5*37.6
=1.5*62.4+1.5*37.6
=1.5*（62.4+37.6）
=1.5*100
=150
二.52*11.1+2.6*778
=2.6*222+2.6*778
=2.6*（222+778）
=2.6*1000
=2600
三.48*1.08+1.2*56.8
=1.2*43.2+1.2*56.8
=1.2*（43.2+56.8）
=1.2*100
=120
四.72*2.09-1.8*73.6
=1.8*83.6-1.8*73.6
=1.8*（83.6-73.6）
=1.8*10
=18