8/63 * 9/70 * 15/28 =
10/63 * 9/28 * 14/15 =
15/56 * 9/56 * 9/70 =
12/35 * 8/105 * 9/10 =
18/35 * 12/35 * 14/45 =
9/56 * 9/28 * 9/20 =
14/45 * 9/14 * 21/40 =
12/35 * 8/63 * 8/15 =
20/21 * 8/21 * 28/45 =
9/70 * 9/35 * 9/28 =
9/35 * 9/56 * 20/63 =
9/280 * 20/63 * 12/35 =
35/72 * 21/40 * 8/105 =
8/9 * 8/63 * 8/63 =
35/36 * 40/63 * 8/35 =
9/14 * 10/21 * 21/40 =
9/56 * 15/56 * 9/70 =
8/105 * 10/63 * 20/21 =
45/56 * 8/63 * 8/35 =
8/63 * 9/35 * 18/35 =
总共20道