3.67×0.74≈ 2.72 32.4÷57≈ 0.57
3.9÷16≈0.24
3.用简便方法计算。 32×1.25×25 =(1.25×8)×(4×25) =10×100 =1000 4.2×0.3+4.2×0.7 =4.2×(0.3+0.7) =4.2×1 =4.2 15.8÷4÷0.25+1.75 =15.8÷(4×0.25)+1.75 =15.8÷1+1.75 =17.55 0.84×101—0.84 =0.84×(101-1) =0.84×100 =84 4.67—(2.98+0.67) =4.67-0.67-2.98 =4-2.98 =1.02 0.36×99 =0.36×100-0.36 =36-0.36 =35.64 0.7×(6.3-2.6)÷0.37 =0.7×(3.7÷0.37) =0.7×10 =7 4.06+3.9+5.94+6.1 =(4.06+5.94)+(3.9+6.1) =10+10 =20 三、解决问题。 1. 480÷(210÷3.5)=8(小时) 答：这辆汽车行驶480千米需要8小时。 2.(66.8-2.8)÷3.2+1=21(层) 答：这幢楼一共有21层。 |
