Question

有42棵楊樹(shù)，杉樹(shù)是楊樹(shù)的3倍，柳樹(shù)比它們的總數(shù)少28棵，柳樹(shù)有多少棵？

Answer 1

分析：有42棵楊樹(shù)，杉樹(shù)是楊樹(shù)的3倍，則杉樹(shù)有42×3棵，則楊樹(shù)與杉樹(shù)共有42×3+42棵，柳樹(shù)比它們的總數(shù)少28棵，根據(jù)減法的意義可知，柳樹(shù)有42×3+42-28棵．

解答：解：42×3+42-28
=126+42-28，
=168-28，
=140（棵）．
答：柳樹(shù)有140棵．

點(diǎn)評(píng)：首先根據(jù)乘法的意義求出杉樹(shù)的棵數(shù)是完成本題的關(guān)鍵．