第1个回答 2016-11-09
1. 6÷ 3/8 – 3/8 ÷6
=1/6x(3/8-3/8)
=1/6x0
=0
2. 4/7 × 5/9 + 3/7 × 5/9
=(4/7+3/7)x5/9
=1x5/9
=5/9
3. 5/2 -（ 3/2 + 4/5 ）
=5/2-3/2-4/5
=1-4/5
=1/5
4. 6 ×（ 1/2 + 2/3 ）
=6x1/2+6x2/3
=3+4
=7
5. 8 × 4/5 + 8 × 11/5
=8x(4/5+11/5)
=8x3
=24
6. 31 × 5/6 – 5/6
=(31-1)x5/6
=30x5/6
=25
7. 4/5 × 25/16 + 2/3 × 3/4
=5/4+1/2
=5/4+2/4
=7/4本回答被网友采纳