全国2007年4月高等教育自学考试数论初步试题_第6页

26.设1≤a≤40, 化成循环小数其循环节长度是（　　　）
A.40                                                         B.8

C.10                                                         D.5

27.51000被17除的余数是（　　　）
A.16                                                         B.13

C.15                                                         D.8

28.下列数中有可能是3个连续排列的奇数之和的数是（　　　）
A. 15                                                        B.14

C.13                                                         D.12

29.3407的个位数字是（　　　）
A.1                                                           B.3

C.7                                                           D.9

30.方程 的正整数解有______组。（　　　）
A.3                                                           B.4

C.5                                                           D.6