56又11分之8除以9 =624/11÷9=6又33分之10
(2又2/9×4/5+2又2/9x6.2-5.8x2又2/9-1/5÷9/20=2又9分之2×(0.8+6.2-5.8-0.2)
=2又9分之2×1
=2又9分之2