(4/5-2/3)×5/8
=(96/120-80/120)×5/8
=2/15×5/8
=1/12
2/9+7÷9+4/5
=2/9+7/9+4/5
=10/45+35/45+36/45
=81/45
2-6/13÷9/26
=2-6/13×26/9
=2-3/4
=4/5