3/12,7/12,11/12,15/12 arithmetic progression.
来源:
jinjing
于
2016-12-13 15:53:49
[
旧帖
] [
给我悄悄话
] 本文已被阅读:次
Common diffrence is 4/12,the next number is 15/12 + 4/12 = 19/12 .