4,13,22,31,45,54,61,( ) A.69 B.70 C.71 D.73
问题描述:
4,13,22,31,45,54,61,( ) A.69 B.70 C.71 D.73
答
选B
两两一组
13-4=9
31-22=9
54-45=9
所以70-61=9