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
80-4*12/3=80-16=64
60+180/20-5=64
4.5-(2.56+0.12+0.86)
15.37-(2.8+2.2)
19.92-9.92+10.35
42*4*25=42*100
80-4*3*4/3=80-16=64,
60+6-5=60+1=61,
4.5-3.54=0.96
15.37-5=10.37
10+10.35=20.35
42*100=4200
64 64 0.96
10.37 20.35 4200
供参考