1 -0.4= | 1÷ ×3= | 0.01÷0.1= | × ÷ × = |
| 0.125×0.125= | 12.9985×3.0023≈ | -0.7+ = | = |
1 -0.4=1.1, | 1÷ ×3=9, | 0.01÷0.1=0.1, | × ÷ × = , |
| 0.125×0.125=0.015625, | 12.9985×3.0023≈39, | -0.7+ =0.3, | = . |
分析:根据分数和小数加减乘除的计算方法进行计算即可;
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按照从左向右的顺序进行计算;12.9985×3.0023把12.9985看作13,3.0023看作3再计算.点评:口算时,注意运算符号和数据,然后再进一步计算即可,能简算的要简算.
-0.4=
×3=
-0.7+
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,