sumaAlgorithm.js

var a1=2;
var a2=4;

function sum(a, b) {
  var res=0;

  var sum = 0;
  var i = 0;

  while (i < b) {
      sum = sum + a;
      i++;
  }

  res = sum;
  return res;
}

console.log(sum(a1, a2));