例:笼子里有若干只鸡和兔,从上面数,有9个头,从下面数,有28只脚,鸡、兔各有几只?
(A)假设法:
(B)用方程解答:
(C)列表法:
鸡 |
1 |
|
|
|
|
|
|
|
兔 |
8 |
|
|
|
|
|
|
|
脚 |
34 |
|
|
|
|
|
|
|
即鸡有 只,兔有 只.