5/6＋（1/3-5/6）(去括号）
=5/6-5/6+1/3
=1/3
3/10＋1/5-1/3
=3/10+2/10-1/3
=5/10-1/3
=1/2-1/3（通分）
=1/6
7/9＋1/12-11/18
=14/18-11/18+1/12
=3/18+1/12
=1/6+1/12
=2/12+1/12
=3/12
=1/4
3-5/11-17/11
=3-（5/11+17/11）
=3-22/11
=3-2
=1
5-4/7-一又七分之三
=5-4/7-10/7
=5-（4/7+10/7）
=5-14/7
=5-2
=3
2-2/3-7/12
=2-（8/12+7/12）
=2-15/12
=2-5/4
=2-1又1/4
=3/4