| 直接写出得数. 21+17= | 78-15= | 200+3000= | 4500-500= |
| 24×2= | 40×3= | 35×2= | 20×6= |
| 36÷3= | 48÷4= | 27÷9= | 80÷4= |
+ = | - = | + = | 1- = |
| 21+17=38, | 78-15=63, | 200+3000=3200, | 4500-500=4000, |
| 24×2=48, | 40×3=120, | 35×2=70, | 20×6=120, |
| 36÷3=12, | 48÷4=12, | 27÷9=3, | 80÷4=20, |
+ = , | - = , | + = , | 1- = . |
分析:根据整数的加减乘除和分数的加减法的计算方法进行计算即可.
点评:口算时,注意看清运算符号和数据.
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