| 直接写得数 12÷ = | 0.6× = | ÷ = | × = | ÷ = |
- = | ×20= | 0× + = | 180÷ = | × = |
解:12÷ =20, | 0.6× =0.5, | ÷ = , | × = , | ÷ = , |
- = , | ×20=12, | 0× + = , | 180÷ =200, | × = . |
分析:分数加减法:要注意先通分成同分母分数,再分母不变,分子相加减;
分数乘法:分子和分母先约分,再计算;
分数除法:先改写成被除数乘除数的倒数,再按照分数乘法的法则进行计算.
点评:此题考查学生看算式快速计算的能力,要注意看清运算符号,根据数据的特点,选用自己喜欢的方法计算.
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