【例題】4,5，( ),14， 23,37
    A.6                 B.7                 C.8                 D.9
    【例題】84,64,47,33，( ),14
    A.12                B.14                C.22                D.24
    【例題】32，23，54，45，( )
    A.76                B.67                C.89                D.78
    【例題】343,453,563，( )
    A.673               B.683               C.773               D.783
    【例題】0,6,24,60,120，( )
    A.186               B.210               C.220               D.226
    【答案】D
    【答案】C
    【答案】A
    【答案】A
    【答案】B