Question

口算

1.2+2.8=	0.9÷0.01=	3.5+7.6=	3×0.2×0.5=	0.96÷0.3=
1.5×0.4=	7÷0.25=	2.5×0.7×0.8=	8-2.5=	16÷1.6=
5.6×1.01=	8×（2.5+0.25）=	0.36+0.64=	64.32÷16=	72.8÷0.8=
8.4×0.2=	8.4÷4.2=	0.05×0.8=	2.56-0.37=	1.25×0.8×0.5=

Answer 1

考点：小数的加法和减法,小数四则混合运算

专题：运算顺序及法则

分析：运用小数的加减、乘除法的计算法则进行计算．

解答：

解：1.2+2.8=4	0.9÷0.01=90	3.5+7.6=11.1	3×0.2×0.5=0.3	0.96÷0.3=3.2
1.5×0.4=0.6	7÷0.25=28	2.5×0.7×0.8=1.4	8-2.5=5.5	16÷1.6=10
5.6×1.01=5.656	8×（2.5+0.25）=22	0.36+0.64=1	64.32÷16=4.02	72.8÷0.8=91
8.4×0.2=1.68	8.4÷4.2=2	0.05×0.8=0.04	2.56-0.37=2.19	1.25×0.8×0.5=0.5

点评：计算加减时注意小数点对齐，注意计算结果中小数部分的位数．