1,9,11,15,17,19,21,27,33,35,37,41,45,49,57,65,72,81合数有,偶数有,3

回答 共1条 2013-03-12 20:09筱璇3|一级写出五个质数,写出五个合数：2,3,5,7,11；4,6,8,9,10.
1~30各数中： 质数有（2,3,5,7,11,13,15,17,19,23,29）合数有（4,6,8,9,10,12,14,15,18,20,21,22,24,26,28,30）奇数有（1,3,5,7,9,11,13,15,17,19,21,23,25,27,29）偶数有（2,4,6,8,10,12,14,16,18,20,22,24,26,28,30）是3的倍数的数有（3,6,9,12,15,18,21,24,27,30）是5的倍数有（5,10,15,20,25,30）是2和5的倍数有（10,20,30）是3和5的倍数有（15,30）是2,3和5的倍数有（30）追问1,9,11,15,17,19,21,27,33,35,37,41,45,49,57,65,72,81合数有,偶数有,3的倍数有