0.625×(1又2/3+3又1/6)+1/6÷1又3/5-5/8
=0.625×(5/3+19/6)+1/6÷8/5-5/8
=5/8×(5/3+19/6)+1/6×5/8-5/8
=5/8×(5/3+19/6+1/6-1)
=5/8×4
=5/2