1、解決問(wèn)題 探究和的奇偶數(shù),平遙實(shí)驗(yàn)小學(xué) 閆愛(ài)蘭,一、復(fù)習(xí)導(dǎo)入，揭示課題,51,39,207,801,48,420,8976,二、探究新知,奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？,二、探究新知,奇數(shù)：5， 7， 9， 11， 偶數(shù)：8，12，20，24，,5712,7916,5813,7815,81220,122436,奇數(shù)奇數(shù)偶數(shù),奇數(shù)偶數(shù)奇數(shù),偶數(shù)偶數(shù)偶數(shù),奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？,二、探究新知,奇數(shù)除以2余1,偶數(shù)除以2沒(méi)有余數(shù),奇數(shù)加偶數(shù)的和除以2還余1，所以，奇數(shù)偶數(shù)奇數(shù)。,奇數(shù)加奇數(shù)的和除以

2、2沒(méi)有余數(shù)，所以，奇數(shù)奇數(shù)偶數(shù)。,偶數(shù)加偶數(shù)的和除以2沒(méi)有余數(shù)，所以，偶數(shù)偶數(shù)偶數(shù)。,奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？,二、探究新知,奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？,偶數(shù),奇數(shù),偶數(shù),二、探究新知,奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？,所以，奇數(shù)偶數(shù)奇數(shù),三、知識(shí)運(yùn)用,三、知識(shí)運(yùn)用,2. 奇數(shù)與奇數(shù)的積是奇數(shù)還是偶數(shù)？奇數(shù)與偶數(shù)的 積是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的積呢？,5735,7963,5840,7856,81296,1424336,奇數(shù)奇數(shù)奇數(shù),奇數(shù)偶數(shù)偶數(shù)