質(zhì)數(shù)合數(shù)問題:(中等難度)舉例回答下面各問題:(1)兩個(gè)質(zhì)數(shù)的和仍是質(zhì)數(shù)嗎?(2)兩個(gè)質(zhì)數(shù)的積能是質(zhì)數(shù)嗎?(3)兩個(gè)合數(shù)的和仍是合數(shù)嗎?(4)兩個(gè)合數(shù)的差(大數(shù)減小數(shù))仍是合數(shù)嗎?(5)一個(gè)質(zhì)數(shù)與一個(gè)合數(shù)的和是質(zhì)數(shù)還是合數(shù)?質(zhì)數(shù)合數(shù)答案:(1)不一定;(2)不能;(3)不一定...2016-04-27