(+0.25)-(-3又8分之1)-(+5又4分之3)-(+4分之1)
=0.25+3+1/8-5-3/4-1/4
=1/4+3+1/8-5-(3/4+1/4)
=1/4+1/8+3-5-1
=2/8+1/8-3
=3/8-3
=-2又5/8