a .2per5 × 15per6 b.1,1per2×3per4 c.2per3×6per8×16per32 d.1,1per2×2,2per3×3,3per4

2/5 × 15/6 = 1

1 1/2 × 3/4 = 3/2 × 3/4 = 9/8 = 1 1/8

2/3×6/8×16/32 = 2/3×3/4×1/2 = 1/4

1 1/2 × 2 2/3 × 3 3/4 = 2/2×8/3×15/4 = 10