小数乘法简便运算课件.ppt

,小数乘法的简便运算,五年级,比较一下,哪边的计算更简便.(3.22.8)0.6 3.20.62.80.61.25230.8 1.250.823,小数 整数,下面计算运用了什么定律.(1.25+2.5)0.8=1.250.8+2.50.82.53.24=3.2(2.54),填空:0.258.94=0.25()()3.22.8-3.20.8=3.2(-)9.21.01=9.2()+9.2()4.10.99=4.1()-4.1(),12.50.438 2.51.2532,5.61.35.68.7 2.5(400.4),3.2993.2 3.21.01,7.210.27.20.2 7.2(100.1),7.21017.2 0.6199,口算:1.2580=50.6=0.60.08=1.25=200.05=4.32=3.510=0.213=,口算:1.2580=100 50.6=30.60.08=0.048 1.25=6200.05=1 4.32=8.63.510=0.35 0.213=0.07,7.11.01 7.1 0.430.99 0.99 3.50.63 3.5,比一比,谁算得又对又快:4.05233.20.7562.4610.886411.546,2.50.99=2.51000.01=2500.01=249.99,2.50.99=2.512.50.01,2.520.1=2.5202.51=502.5=52.5,2.520.1=2.5202.50.1,1.25 2.532=1.2582.54=1010=20,1.25 2.532=(1.258)(2.54),2.54.8=2.552.50.2=12.50.5=12,2.54.8=2.541.2,