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