999又7/8+99又3/4+91/2+7/8
= (1000-1/8)+(100-2/8)+(50-36/8)+(1-1/8)
= 1000+100+50+1-1/8-2/8-36/8-1/8
= 1150-(1/8+2/8+36/8+1/8)
= 1150-40/8
= 1150-5
1145