4.8× 5/4 + 1/4 = 41/45.6÷ 3/8 – 3/8 ÷6 = 255/166.4/7 × 5/9 + 3/7 × 5/9 = 5/97.5/2 -（ 3/2 + 4/5 ） = 1/5 8.7/8 + （ 1/8 + 1/9 ） = 10/99.9 × 5/6 + 5/6 = 25/310.3/4 × 8/9 - 1/3 = 1/311.7 × 5/4...