计算下面各题,能简算的要用简便方法计算80-12×4÷3 60+180÷20-5 4.5-(2.68+0.86)15.37-2.8-2.2 19.92+10.35-9.92 42×4×25

问题描述:

计算下面各题,能简算的要用简便方法计算
80-12×4÷3 60+180÷20-5 4.5-(2.68+0.86)
15.37-2.8-2.2 19.92+10.35-9.92 42×4×25

80-12×4÷3=80-(12÷3)×4=80-16=64
60+180÷20-5=60+90-5=145
15.37-2.8-2.2=15.37-(2.8+2.2)=15.37-5=10.37
19.92+10.35-9.92=19.92-9.92+10.35=10+10.35=20.35
42×4×25=42×(4×25)=42×100=4200