(4/7)÷(-2又2/5)-(3/7×5/12-5/3)
=4/7÷(-12/5)-3/7×5/12+5/3
=-4/7×5/12-3/7×5/12+5/3
=5/12×(-4/7-3/7)+5/3
=5/12×(-1)+5/3
=-5/12+5/3
=15/12
=5/4