ESG

有兴趣的叫你们家小孩试试。

50束鲜花中,有16束插着月季花,有15束插着马蹄莲,有21束插着白兰花,有7束既有月季花又有马蹄莲,有8束既有马蹄莲又有白兰花,有10束既有月季花又有白兰花,还有5束这三种花都有.则50束鲜花中,这3种花都没有的有几束?

jliu37

Draw a pie chart with 3 circles. The problem is going to be easy if you pick the correct method, which is what Chinese Olympics focus on training. When your kid is fed up with the easy problems here, they can use one or two problems like this to polish their brain a bit.
However, if a lot of problems like this came from some class you sent him to, you should double check your own decision.

ESG

对成年人来说这道题不是太困难，尤其学过集合的。问题是对小学四年级的学生是不是有点过分了？现在中国很多好一点的私立中学使用奥数题来招生，对于数学天份一般的学生，只有在平时狂做练习，即使他们并不是完全理解原理。

2dian

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2dian

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