1- = | 12-12×0.1= | - = | 0.3+ = | 1.66÷2= |
+ = | 7- = | 23+52= | -0.75= | 50×25×1.2= |
解:1- = , | 12-12×0.1=10.8, | - = , | 0.3+ =1, | 1.66÷2=0.83, |
+ = , | 7- =6 , | 23+52=33, | -0.75=0.05, | 50×25×1.2=1500. |
分析:12-12×0.1,先算乘法,再算减法;
23+52=,表示求3个2的乘积加上2个5的乘积和,计算得解;
50×25×1.2改写成(10×25)×(5×1.2),从而巧算;
其它算式按照分数、小数加减法的计算方法计算得解.
点评:此题考查基本的口算,根据数据和符号的特点,灵活选择合适的方法计算.
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