Question

如果a是奇數(shù)，b是偶數(shù)，且a＜b，下列各式結果是奇數(shù)的有（　　）

A．a+a

B．a+b

C．b+b

D．b-a

E．a×a

F．a×b

  

Answer 1

分析：根據(jù)偶數(shù)、奇數(shù)的意義：是2的倍數(shù)的數(shù)叫做偶數(shù)；不是2的倍數(shù)的數(shù)叫做奇數(shù)．再根據(jù)偶數(shù)和奇數(shù)的性質：奇數(shù)與奇數(shù)的和或差是偶數(shù)；偶數(shù)與偶數(shù)的和或差是偶數(shù)；奇數(shù)與偶數(shù)的和或差是奇數(shù)；奇數(shù)與奇數(shù)的積是奇數(shù)．據(jù)此進行解答．

解答：解：根據(jù)分析可知：奇數(shù)-偶數(shù)=奇數(shù)；偶數(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)．
故選：B、D、E．

點評：此題考查的目的是使學生理解偶數(shù)、奇數(shù)的意義，掌握偶數(shù)和奇數(shù)的性質．