3／4一1／12＝，5／6＋7／18＝，5／6一1／4＝，3／5一1／10＝

解: 3/4-1/12
=(9-1)/12
=8/12
=2/3
5/6+7/18
=15/18+7/18
=22/18
=11/9
5/6-1/4
=10/12-3/12
=7/12
3/5-1/10
=6/10-1/10

=5/10
=1/2