四年级数学下册第六单元小数简便计算专项练习1.计算下面各题(能简算的要简算)。6.78+2.04+7.22+5.960.25×4.42.8×101-2.8=(6.78+7.22)+(2.04+5.96)=0.25×4+0.25×0.4=2.8×(101-1)=14+8=1+0.1=2.8×100=22=1.1=2802.计算下面各题，怎样简便就怎样计算。1.29-3.7+9.71-6.3300-2730÷91-70400-(1300÷65+35)=1.29+9.71-(3.7+6.3)=300-30-70=400-(20+35)=11-10=300-(30+70)=400-55=1=200=345125×486.45-(2.31-1.55)64×39+37×39-39=125×8×6=6.45-2.31+1.55=39×(64+37-1)=1000×6=6.45+1.55-2.31=39×100=6000=8-2.31=39003.怎样简便就怎样计算。103×87-93×873000÷125÷8=(103-93)×87=3000÷(125×8)=10×87=3000÷1000=870=36.74+12.62+24.38+3.2623.4-8.54-1.46=(6.74+3.26)+(12.62+24.38)=23.4-(8.54+1.46)=10+37=23.4-10=47=13.46.92-(3.2+1.92)101×78-78=6.92-1.92-3.2=(101-1)×78=5-3.2=100×78=1.8=78004.怎样算简便怎样。5.02-3.5+0.982.88+2.3+4.77300÷(73×25)=(5.02+0.98)-3.5=2.88+(2.3+4.7)=7300÷73÷25=6-3.5=2.88+7=100÷25=2.5=9.88=41050÷15÷780-12.4-7.6568-(68+178)=1050÷(15×7)=80-(12.4+7.6)=568-68-178=1050÷105=80-20=500-178=10=60=3225.简便运算。3.27+5.49-1.27+4.519.75-(6.75+0.4)=3.27-1.27+(5.49+4.51)=9.75-6.75-0.4=2+10=3-0.4=12=2.610.27-0.34+1.73-2.6612.457-(2.457-4.5-5.5)=10.27+1.73-(0.34+2.66)=12.457-2.457+(4.5+5.5)=12-3=10+10=9=206.怎样算简便就怎样算：9.25×9.9+92.5%=92.57.用简便方法计算。①25×1.25×32②(3.75-2.9+2.25)÷31%=25×1.25×4×8=(3.75+2.25-2.9)÷31%=(25×4)×(1.25×8)=(6-2.9)÷0.31=1000=108.用你喜欢的方法计算5/8+3/4×60%12.5×25%×20+3.2=5/8+3/4×3/5=12.5×¼×20+3.2=5/8+9/20=62.5+3.2=4340=65.70.875×25+75×87.5%+87.56.7-3.25+13.3-0.75=0.875×25+75×0.875+0.875×100=(6.7+13.3)-(3.25+0.75)=0.875×(25+75+100)=20-4=175=169.计算下面各题。你认为怎样简便就怎样算。1.2÷2.5(30.5-8.22)×0.434.7÷12.5÷0.8=(1.2×4)÷(2.5×4)=22.28×0.4=34.7÷(12.5×0.8)=4.8÷10=8.912=34.7÷10=0.48=3.4710.能简算的要简算。125%-68%+0.7(45%+25%)×434%+79%+21%+66%=1.25-0.68+0.7=(0.45+0.25)×4=0.34+0.79+0.21+0.66=0.57+0.7=0.7×4=(0.34+0.66)+(0.79+0.21)=1.27=2.8=2120%+89%+11%2-45%-55%36%×1.7+1.7×64%=1.2+0.89+0.11=2-0.45-0.55=0.36×1.7+1.7×0.64=1.2+(0.89+0.11)=2-(0.45+0.55)=(0.36+0.64)×1.7=2.2=1=1.711.计算下面各题，怎样简便怎样计算，要写出必要的计算过程。10-2.8-7.216.8÷0.5÷23.7×0.25×4=10-(2.8+7.2)=16.8÷(0.5×2)=3.7×(0.25×4)=10-10=16.8÷1=3.7×1=0=16.8=3.712.怎样算简便就怎样算。25.86+7.8-5.860.8×3.37×12.53.2+6.8×1.25×8=25.86-5.86+7.8=(0.8×12.5)×3.37=3.2+6.8×(1.25×8)=20+7.8=10×3.37=3.2+6.8×10=27.8=33.7=3.2+68918-(107+218)45×9825×(20+4)=918-107-218=45×(100-2)=25×20+25×4=918-218-107=45×100-45×2=500+100=700-107=4500-90=600=593=441013.计算下面各题，怎样算简便就怎样算。8.49+(4.64-2.14)×0.644.2×99+4.2=8.49+2.5×0.64=4.2×(99+1)=8.49+2.5×4×0.16=4.2×100=10.09=420