6 3/11:(9 3/8-7 1/2+11/20+3 23/40)×5 1/2×1 15/23= 1 220/407
1. 9 3/8-7 1/2=2 (3/8-1/2)=2(3-4/8)=2 (-1/8)=1 7/8
2. 11/20+3 23/40=34 (11/20+23/40)=34 (22+23/40)=34 45/40=35 1/8
3. 1 7/8+35 1/8=37
4. 6 3/11:37=69/11:37=69/407
5. 69/407×5 1/2=69/407×11/2=69×11:407×2=
=759/814
6. 759/814×1 15/23=759/814×38/23=759×38:
:814×23=627/407= 1 220/407