群里“唯一的雨”小朋友提问：鸡兔同笼问题，知道脚的总数和兔比鸡多几只，怎样计算鸡和兔的只数？ziyo老师：找一道这种类型的题目发在群里，我来解答。题目如下：鸡兔同笼，共306只脚，而且兔比鸡多39只，问鸡，兔各几只？

数学题解答：设鸡有x只，则兔有（x+39）只。根据题意，有：鸡脚总数+兔脚总数＝306，列出方程：

2x+(x+39)×4＝306→红加号前的是鸡脚总数，红加号后的是兔脚总数。

2x+4x+156=306

6x+156=306

6x=150

x=25

兔有：25+39＝64（只）。

算术方法（素心兰老师提供）：先去掉多出来的39只兔的脚数，这时鸡、兔只数同样多。一只鸡、一只兔为一组，鸡兔正好配对。每组中鸡兔共有6只脚，脚数除以6算出组数，也就是此时鸡的只数或兔的只数。

（306-39×4）÷（4+2）=25（只）→鸡 

25+39=64（只）→原来兔的只数

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