简便计算方法42+126*58=?
问题描述:
简便计算方法42+126*58=?
答
42+126*58
= 42*(126 - 125) + 126*58
= (42 + 58)*126 - 42*125
= 100*126 - (40 + 2)*125
= 12600 - 40*125 - 2*125
= 12600 - 5000 - 250
= 7600 - 250
= 7350