数学上册复习简便运算课件.ppt

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+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）=14.68-10=4.68,8.75+3.37-0.75+4.63,=8.75-0.75+3.37+4.63=(8.75-0.75)+(3.37+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-（）,=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)=5.32-3=2.32,14.42.43=14.4(2.43)=14.47.2=2,12.319-1230.9=1231.9-1230.9=123（）=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),2.229.96.666.7,=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=78,1-15.62.1=15.6(13.1-1-2.1)=15.610=156,=4.81-4.80.5=4.8(1-0.5)=4.80.5=2.4,6.1-5.9+3.9-4.1,15.89+（）,31.2-（）,