1234/5678 < 2345/6789
因为,
1234/5678 < 1234/5000 < 2000 / 5000 = 2/5
2345/6789 > 2345 / 7000 > 3000/7000 = 3/7
2/5 < 3/7
所以,
1234/5678 < 2345/6789