無(wú)解 因?yàn)?單數(shù)+單數(shù)=雙數(shù)(如3+5=8)雙數(shù)+雙數(shù)=雙數(shù)(如2+4=6)單數(shù)+雙數(shù)=單數(shù)(如3+4=7)此題要求把30分成7個(gè)單數(shù),可是7個(gè)單數(shù)相加,兩兩組合根據(jù)單數(shù)+單數(shù)=雙數(shù),形成4個(gè)雙數(shù)和1個(gè)單數(shù),4個(gè)雙數(shù)兩兩組合,根據(jù)雙數(shù)+雙數(shù)=雙數(shù),又形成兩個(gè)雙數(shù),這兩個(gè)雙數(shù)相加的和仍然是雙數(shù),這個(gè)雙數(shù)再加上最開(kāi)始剩下的那個(gè)單數(shù),根據(jù)單數(shù)+雙數(shù)=單數(shù),和只能是個(gè)單數(shù),也就是說(shuō)9個(gè)單數(shù)的和只能是單數(shù),而30是雙數(shù),所以30不能分成7個(gè)單數(shù)
記得采納啊