第5课时 小数加、减法的简算 5.93 +0.19+2.81 3.070.381.62 7.32.77.32.7 1.27+3.9+0.73+16.1 48.42.7851.60.78 23.40.813.47.2 139.46( 58.74+ 19.46 )答案提示5.93 +0.19+2.81 3.070.381.62 =5.93+(0.19+2.81) =3.07+(0.38+1.62)=5.93+3 =3.07+2=8.93 = 5.077.32.77.32.7 1.27+3.9+0.73+16.1 =7.3-7.3+2.7+2.7 =(1.27+0.73)+(3.9+16.1)=0+2.7+2.7 =2+20=5.4 =2248.42.7851.60.78 23.40.813.47.2=(48.4+51.6)+(2.78-0.78) =(23.4-13.4)-(0.8+7.2)=100-2 =10-8=98 =2139.46 ( 58.74+ 19.46 )=139.46-19.46-58.74=120-58.74=61.26
