41又1/3×3/4＋51又1/4×4/5＋61又1/5×5/6
=(40+4/3)×3/4＋(50+5/4)×4/5＋(60+6/5)×5/6
=40*3/4+1+50*4/5+1+60*5/6+1
=30+1+40+1+50+1
=123