(50/9-0.8+22/禅塌首友9)×12.5
=(72/贺芹圆9-0.8)×12.5
=(8-0.8)×12.5
=8×12.5-0.8×12.5
=100-10
=90
(50/首友9-0.8+22/禅塌9)×12.5
=(50/9+22/贺芹圆9-0.8)×12.5
=(72/9-0.8)×12.5
=(8-0.8)×12.5
=8×12.5-0.8×12.5
=100-10
=90
解：（旅滑含50/9+22/9-0.8）x12.5
=（拆笑让冲8-0.8）x12.5
=8x12.5-0.8x12.5
=100-10
=90