125又7/8除以（11又3/4减4又3/20加2.25减7/20)
=125又7/8除以（11+3/4-4-3/20+2+1/4-7/20)
=125又7/8除以（11-4+2+3/4+1/4-7/20-3/20)
=125又7/8除以（10-1/2)
=1007/8除以19/2
=1007/8*2/19
=53*19/8*2/19
=53/4
=13+1/4
=13又1/4