用0,1,2,3,4,可以组成多少个小于1000的没有重复数字的自然数?答:一共有69个没有重复数字的自然数。个位数:0,1,2,3,4,十位数:10,12,13,14,20,21,23,24,30,31,32,34,40,41,42,43 百位数:102,103,104,120,123,124,130,132,134,140,142,143,201,203,204,210,213,214,230,231,234,240,241,243, 301,302,304,310,312,314,320.321.324...