(0.75+0.2)/0.25*2.5
=（3/4+1/5)×4×5/2
=3/4×4×5/2+1/5×4×5/2
=15/2+2
=7.5+2
=9.5
或：
(0.75+0.2)/0.25*2.5
=0.95×4×2.5
=0.95×（4×2.5）
=0.95×10
=9.5