题目内容
【题目】用合适的方法计算。
4.5×0.7+5.5×0.7 18.5-3.21-4.79
3.78-1.46 + 1.54 14.2×9.9+1.42
【答案】7 10.5
3.86 142
【解析】
4.5×0.7+5.5×0.7 18.5-3.21-4.79
=(4.5+5.5) ×0.7 =18.5-(3.21+4.79)
=10×0.7 =18.5-8
=7 =10.5
3.78-1.46 + 1.54 14.2×9.9+1.42
=2.32+1.54 =14.2×9.9+14.2×0.1
=3.86 =(9.9+0.1)×14.2
=142