用0,1,2,3,4,这5个数字,组成无重复数字的五位数,偶数几种?答:五位数为偶数,个位需为0,2,4 当个位为0时,共有N1=A(4,4)=24种 当个位为2时,0不能为万位,共有N2=A(3,1)*A(3,3)=18种 当个位为4时,0不能为万位,共有N3=A(3,1)*A(3,3)=18种 所以用0,1,2,3,4,这5个数字,组成无重复数字的五位数,偶数有N=N1+N2+N3=60种 ...
0-9可以组成多少组五位数的数据答:11234,12234,13345,14456,15567,17789,11345,11546,11567,11678,11789,12245,12256,12278,12289,13356,13367,13389,22345,22456,22567,22678,22789,33124,33456,33567,33678,33891,44156,44167,44567,44789,44678,44123,55678,55789,55123,55234,55612,55236,55238,55239,55894,55467,55194,66123,66124,...