3/35÷3/35×2
=1×2
=2
4/9×8/7×9/4
=8/7
4/7×（3/4＋7/9）
=4/7×3/4+4/7×7/9
=3/7+4/9
=（27+28）/63
=55/63
5/8÷3/7÷5/4
=5/8×7/3×4/5
=7/6