采纳一下谢谢
等
3/8+3/8+7/10-2/5
=(3/8+3/8)+(7/10-2/5)
=3/4+3/10
=21/20
3/5+1/10+21/22+4/11
=(3/5+1/10)+(21/22+4/11)
=7/10+29/22
=111/55
5/3-(3/5+1/3)+3/5
=5/3-1/3-3/5+3/5
=(5/3-1/3)+(3/5-3/5)
=4/3+0
=4/3
65/3-51/7-17/3-19/7
=(65/3-17/3)-(51/7+19/7)
=16-10
=6