Question

2．校園里有楊樹(shù)50棵，柳樹(shù)40棵，楊樹(shù)棵數(shù)是柳樹(shù)棵數(shù)的125%，柳樹(shù)棵數(shù)是楊樹(shù)棵數(shù)的80%，楊樹(shù)比柳樹(shù)多25%，柳樹(shù)比楊樹(shù)少20%．

Answer 1

分析 把柳樹(shù)的棵數(shù)看成單位“1”，用楊樹(shù)的棵數(shù)除以柳樹(shù)的棵數(shù)，即可求出楊樹(shù)是柳樹(shù)的百分之幾；
把楊樹(shù)的棵數(shù)看成單位“1”，用柳樹(shù)的棵數(shù)除以楊樹(shù)的棵數(shù)，即可求出柳樹(shù)是楊樹(shù)的百分之幾；
先把柳樹(shù)的棵數(shù)看成單位“1”，用楊樹(shù)的棵數(shù)減去柳樹(shù)的棵數(shù)，求出楊樹(shù)比柳樹(shù)多的棵數(shù)，再用多的棵數(shù)除以柳樹(shù)的棵數(shù)即可求出楊樹(shù)比柳樹(shù)多百分之幾；
先把楊樹(shù)的棵數(shù)看成單位“1”，用楊樹(shù)的棵數(shù)減去柳樹(shù)的棵數(shù)，求出柳樹(shù)比楊樹(shù)少的棵數(shù)，再用少的棵數(shù)除以楊樹(shù)的棵數(shù)即可求出柳樹(shù)比楊樹(shù)少百分之幾．

解答 解：50÷40=125%
40÷50=80%
（50-40）÷40
=10÷40
=25%
（50-40）÷50
=10÷50
=20%
答：楊樹(shù)棵樹(shù)是柳樹(shù)棵樹(shù)的125%，柳樹(shù)棵樹(shù)是楊樹(shù)棵樹(shù)的80%，楊樹(shù)比柳樹(shù)多25%，柳樹(shù)比楊樹(shù)少20%．
故答案為：125，80，25，20．

點(diǎn)評(píng) 本題是求一個(gè)數(shù)是另一個(gè)數(shù)的百分之幾，關(guān)鍵是看把誰(shuí)當(dāng)成了單位“1”，單位“1”的量為除數(shù)．