计算下面各题,能简算的要简算,2/3＋7/10＋1/3 5/9＋8/15＋1/15＋4/9 2/3＋3/7＋4/3＋3/

2/3＋7/10＋1/3
=（2/3+1/3）+7/10
=1+7/10
=1.7或17/10
5/9＋8/15＋1/15＋4/9
=（5/9+4/9）+（8/15+1/15）
=1+9/15
=24/15
2/3＋3/7＋4/3＋3/7
=（2/3+4/3）+（3/7+3/7）
=2+6/7
=20/7
7/12＋3/8＋5/12
=7/12+5/12+3/8
=1+3/8
=11/8
7/6-（1/6＋2/3）
=7/6-1/6-4/6
=6/6-4/6
=2/6
=1/3
3/4-（3/4-1/3）
=3/4-3/4+1/3
=0+1/3
=1/3