function?addTogether()?{??//?Function?to?check?if?a?number?is?actually?a?number ??var?checkNum?=?function(num)?{???? ??????if?(typeof?num?!==?'number')?{?????? ??????????return?undefined; ??????}?else{ ??????????return?num; ??????} ??};?? ?? ??if?(arguments.length?>?1)?{???? ??????var?a?=?checkNum(arguments[0]);???? ??????var?b?=?checkNum(arguments[1]);???? ??????if?(a?===?undefined?||?b?===?undefined)?{?????? ??????????return?undefined; ??????}?else?{?????? ??????????return?a?+?b; ??????} ??}?else?{?? ????????var?c?=?arguments[0]; ????????if?(checkNum(c))?{?????? ????????????return?function(arg2)?{ ????????????????if?(c?===?undefined?||?checkNum(arg2)?===?undefined)?{?????????? ????????????????????return?undefined; ????????????????}?else?{???????? ????????????????????return?c?+?arg2; ????????????????} ????????????}; ????????} ??} } addTogether(2)(3);