原式=(5/6-0.75)×12/25÷4/5=(5/6-3/4)×12/25x5/4=(5/6-3/4)×3/5=5/6x3/5-3/4x3/5=1/2-9/20=10/20-9/20=1/20
(5/6-0.75)×12/25÷4/5=(5/6-3/4)×12/25x5/4=(10/12-9/12)×3/5=1/12x3/5=1/20
