Question Number 32395 by saru53424@gmail.com last updated on 24/Mar/18
$$\mathrm{1}+\mathrm{1} \\ $$
Commented by abdo imad last updated on 24/Mar/18
$$\mathrm{1}+\mathrm{1}\:=\mathrm{2}\:{inside}\:{k}\:/{car}\left({k}\right)\neq\mathrm{2} \\ $$$$\mathrm{1}+\mathrm{1}\:=\mathrm{0}\:{inside}\:{Z}/\mathrm{2}{Z} \\ $$$$\mathrm{1}+\mathrm{1}\:=−\mathrm{1}\:{inside}\:{Z}/\mathrm{3}{Z}…. \\ $$