(-3又7分之5+(-15.5)+(+18又7分之2)加(+5又2分1)
=-3-5/7-15-1/2+18+2/7+5+1/2
=(-3-15+18+5)+1/2-1/2+2/7-5/7
=5+2/7-5/7
=5-3/7
=4+4/7
=4又4/7