Ta có : abcabc : abc
= (abc000 + abc) : abc
= (abc.1000 + abc) : abc
= abc . 1001 : abc
= 1001 (đpcm)
abcabc= abc.1000+abc
= abc.(1000+1)
= abc.1001
suy ra abcabc:abc = 1001 k nha
abcabc : abc
= (abc000 + abc) : abc
= (abc.1000 + abc) : abc
= abc . 1001 : abc
= 1001 (đpcm)