[destus]

Zmicer,

var arr = [];
arr [0] = "1 + 2  ";
arr [1] = "3 ^2 ";
arr [2] = "2+5 ";
arr [3] = "1 +2";

var newArr = arr.map(str => `${str}=${eval(str.replace('^', '**'))}`);
alert(newArr);