设
A = 3/2 × 5/4 × 7/6 × ...× 99/98
B = 2/1 × 4/3 × 6/5 × ...× 98/97 × 100/99
因为 3/2 < 2/1,5/4 < 4/3,7/6 < 6/5,...,99/98 < 98/97,1 < 100/99
所以 A = 3/2 × 5/4 × 7/6 × ...× 99/98 × 1 < 2/1 × 4/3 × 6/5 × ...× 98/97 × 100/99 = B
又因为 A × B = 3/1 × 5/3 × 7/5 × ...× 99/97 × 100/99 = 100
所以 A × A < A × B = 100
所以 A = 3/2 × 5/4 × 7/6 × ...× 99/98 < 10/1