3/4乘以5/6+3/4乘以1/6=5/8+1/8=6/8=3/4
3/4*5/6+3/4*1/6=3/4*(5/6+1/6)=3/4*1=3/4
（3/4）×（5/6）+（3/4）×（1/6）=（3×5+3×1）/（4×6） =（3×6）/(4×6) =3/4
