题目内容
先估算,再笔算.
66+289=
589+135=
549+237=
66+289=
589+135=
549+237=
分析:先把算式中的因数看成和它接近的整十、整百数,再相乘进行估算;然后根据乘法竖式计算的方法求解.
解答:解:66+289≈70+300=370
![](http://thumb.1010pic.com/pic3/upload/images/201401/50/55beab21.png)
589+135≈600+130=730
![](http://thumb.1010pic.com/pic3/upload/images/201401/50/9a8220f4.png)
549+237≈550+250=800
![](http://thumb.1010pic.com/pic3/upload/images/201401/50/a4418afb.png)
![](http://thumb.1010pic.com/pic3/upload/images/201401/50/55beab21.png)
589+135≈600+130=730
![](http://thumb.1010pic.com/pic3/upload/images/201401/50/9a8220f4.png)
549+237≈550+250=800
![](http://thumb.1010pic.com/pic3/upload/images/201401/50/a4418afb.png)
点评:本题考查了整数乘法估算以及笔算的方法,计算时要细心,注意把数位对齐.
![](http://thumb2018.1010pic.com/images/loading.gif)
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