(-64)+17+(-23)+68,怎么算,简便
问题描述:
(-64)+17+(-23)+68,怎么算,简便
答
=-60-4+10+7-20-3+60+8
=(-60+60)+(7-4-3)+(10-20)+8
=-10+8
=-2口算思路,十位两个60,个位3+4=7