// Average the answered scores; blank cells import as "".

const scores = [4, "", 5, 0, 3];

let sum = 0;

let answered = 0;

for (const s of scores) {

  if (s == "") continue;

  sum += s;

  answered += 1;

}

const avg = Math.round((sum / answered) * 100) / 100;

console.log(avg);

// expected: 3

// actual:   4  (!)