Question

1-20总中,质数、合数、奇数、偶数有哪些

Answer 1

质数2,3,5,7,11,13,17,19、

合数4,6,8,9,10,12,14,15,16,18,20、

奇数1,3,5,7,9,11,13,15,17,19、

偶数2,4,6,8,10,12,14,16,18,20