#32 » gửi bởi Tolabocau » 20/10/2012 20:01 » @90638
Goi so do la abcd, vi la so chan => d={0,2,4,6} th1:d=0, a#0 a co 6 cach chon b co 5 c co 4 => co 6x5x4 cach lap th2:d={2,4,6}, a#0 a co 5 cach chon b co 5 c co 4 => co 5x5x4 cach lap kqa = th1 + th2