五年级数学上册复习简便运算.ppt

1、人教版五年级上册,分宜县凤阳中心学校 敖霞梅,复习简便运算,=1250.81.3 =(1250.8)1.3 =100 1.3 =130,1251.30.8,=0.251.20.9 =0.25(40.3)0.9 =(0.254)0.30.9 =10.30.9 =0.27,0.250.91.2,=(200-1)0.88 =2000.88-10.88 =176-0.88 =175.12,1990.88,9010.3,= 90 （10+0.3） =9010+900.3 =900+27 =927,2.3715-2.375,=2.37（15-5） =2.3710 =23.7,9.79.799,= 9.71

2、+9.799 =9.7（1+99） =9.7100 =970,10.96+1090.4,=1090.6+1090.4 =109（0.6+0.4） =1091 =109,50.52.50.2,=50.5（2.50.2） =50.55 =10.1,括号前面是除号，去掉括号要变号，乘号变除号，除号变乘号,2.4（3.65）,=2.43.65 =2.453.6 =123.6 =2,14.68-7.82-2.18,=14.68-（7.82+2.18） =14.68-10 =4.68,8.75+3.37-0.75+4.63,= 8.75-0.75+3.37+4.63 =(8.75-0.75)+(3.37+

3、4.63) =8+8 =16,没有括号的同一级运算可以换位置,13.75-（6.38+3.75）,=13.75-6.38-3.75 =(13.75-3.75)-6.38 =10-6.38 =3.62,26.06-（9.06-5.6）,=26.06-9.06+5.6 =(26.06-9.06)+5.6 =17+5.6 =22.6,特殊,括号前面是减号，去掉括号要变号，加号变减号，减号变加号,5.32-2.16-0.84 =5.32-(2.16+0.84) =5.32-3 =2.32,14.42.43 =14.4(2.43) =14.47.2 =2,12.319-1230.9 =1231.9-12

4、30.9 =123（1.9-0.9） =1231 =123,0.2536 =0.2549 =19 =9,2.5160.7 =2.5(44)0.7 =(2.54)(40.7) =10 2.8 =28,6.3302 =6.3(300+2) =6.3300+6.32 =1890+12.6 =1902.6,1.268+81.74 = (1.26+1.74) 8 =38 = 24,1.251.191.6 =1.251.19(80.2) =1.25(80.2)1.19 =(1.258)(0.21.19) =100.238 =2.38,1.252.532,3201.258,17.8(1.784),2.229

5、.96.666.7,=1.252.5(48) =(1.258)(2.54) =1010 =100,=320(1.258) =32010 =32,=17.81.784 =14 =0.25,=2.22(33.3)+6.666.7 =(2.223) 3.3+6.666.7 =6.663.3+6.666.7 =6.66(3.3+6.7) =6.6610 =66.6,4.87.8780.52,15.613.115.615.62.1,(1.250.125)8,4.84.80.5,=1.258-0.1258 =10-1 =9,=4.87.8+7.85.2 =7.8(4.8+5.2) =7.810 =78,=15.613.1-15.61-15.62.1 =15.6(13.1-1-2.1) =15.610 =156,=4.81-4.80.5 =4.8(1-0.5)