Question

既是偶數(shù)也是質(zhì)數(shù)的數(shù)有______個(gè)，是______．偶數(shù)+偶數(shù)=______，偶數(shù)+奇數(shù)=______，奇數(shù)+奇數(shù)=______；奇數(shù)+奇數(shù)+奇數(shù)=______，奇數(shù)+偶數(shù)+偶數(shù)=______，奇數(shù)+奇數(shù)+偶數(shù)=______．

Answer 1

根據(jù)偶數(shù)與質(zhì)數(shù)定義可知：既是偶數(shù)也是質(zhì)數(shù)的數(shù)有1個(gè)，是2；
根據(jù)數(shù)的奇偶性可知：偶數(shù)+偶數(shù)=偶數(shù)，偶數(shù)+奇數(shù)=奇數(shù)，奇數(shù)+奇數(shù)=偶數(shù)；奇數(shù)+奇數(shù)+奇數(shù)=奇數(shù)，奇數(shù)+偶數(shù)+偶數(shù)=奇數(shù)，奇數(shù)+奇數(shù)+偶數(shù)=偶數(shù)．
故填：1，2；偶數(shù)，奇數(shù)，偶數(shù)，奇數(shù)，奇數(shù)，偶數(shù)．