const myArr = [];
 
for(let x=0; x<10; x++){
  let val1 = 5 * x;
  let val2 = x * x;
  let res = cal(val1, val2, "+");
  myArr.push(res);
}
console.log(myArr);
function cal(a, b, op) {
  if (op == "-") {
    return a - b;
  } else {
    return a + b;
  }
}