1、,练习十二,复习旧知,课堂小结,课后作业,小数乘法和除法,巩固练习,5,复习旧知,小数乘小数的计算方法。,小明房间的面积是多少平方米?,3.83.2(),下面是小明房间和外面阳台的平面图。,小明房间的面积是多少平方米?,3.83.2(),10,10,6,7,4,1,1,6,2,1,1,6,7,4,1,1,6,2,1,1,100,.,12.16,平方米,积的小数位数不够的小数乘法。,小明在阳台上摆放了一个花架,它的底面是边0.28米的正方形。这个花架的占地面积是多少平方米?,0.0784,答:花架的占地面积是 平方米。,0.280.28(平方米),0.0784,在积里点小数点时,位数不够的,在前
2、面用0补足。,0.2 8,0.2 8,4,2,2,5,6,0,.,0,7,8,4,求积的近似值的方法。,王大伯家前年收入3.18万元,去年的收入是前年的1.6倍。去年大约收入多少万元?,(得数保留两位小数),3.181.6,3.1 8,1.6,1,5,5.09,(万元),答:去年他家大约收入5.09万元。,9,0,8,3,1,8,0,8,8,.,巩固练习,0.72,7.2,7.2,0.072,7.2,根据第一栏的积,写出其它栏的积。,0.670.13 1.020.76 0.04514 0.090.84 0.322.05 0.190.25,0.0871,0.7752,0.63,0.0756,0.
3、656,0.0475,一台拖拉机每小时耕地0.5公顷,1.2小时可耕地多少公顷?0.75小时可耕地多少公顷?,0.51.20.6(公顷),0.50.750.375(公顷),答:1.2小时可耕地0.6公顷,0.75小时可耕地0.375公顷。,直接写出得数。0.70.7 1.110 0.240.2 3.50.1 0.20.4 0.65,0.49,11,0.048,0.35,0.08,3,计算下面各题,得数保留一位小数。,5.23.4,8,0,2,17.7,6,5,1,8,6,7,1,.,1.326.8,9.0,6,5,0,2,9,6,7,9,.,8,7,1,计算下面各题,得数保留一位小数。,2.93.14,9.1,6,2,8,8,2,6,0,1,.,9,6,2,计算下面各题,得数保留两位小数。,0.732.02,