| 734-199= | + = | 0.6×0.5= | 1÷0.5= |
4÷9× = | 0.25×4÷ = | ( + )×30= | 9.9÷1 = |
| 715÷80≈ | 498+3007≈ | 46×101≈ | 356÷61≈ |
| 734-199=535, | + = , | 0.6×0.5=0.3, | 1÷0.5=2, |
4÷9× = , | 0.25×4÷ = , | ( + )×30=17, | 9.9÷1 =9, |
| 715÷80≈9, | 498+3007≈3500, | 46×101≈4600, | 356÷61≈6. |
分析:根据整数、分数和小数加减乘除的计算方法进行计算即可.
(
+
)×30根据乘法分配律进行计算.点评:口算时,注意运算符号和数据,然后再进一步计算即可.
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