five friends met and they shook hands with each other.how many hand shakes took place?please write chinese.
问题描述：
five friends met and they shook hands with each other.how many hand shakes took place?
please write chinese.
答
20次
答
五个朋友见面，他们之间两两握手，问共握手多少次。
答案：
5*4/2=10次
答
5个朋友见面,他们相互握手.问：他们一共握了几次手?（每个人和别人共握手4次,共有五个人,所以是握手20次）