const marks = [80];
const grade = ['A', 'B', 'C', 'D', 'F'];
let sum = 0;
console.log(checkGrade(marks));
function checkGrade(array) {
for (let item of array)
sum += item;
const avg = sum / array.length;
let gradePoint = Math.floor((100 - avg) / 10);
return gradePoint % 10;
}as Your code, the avg is = 80
and (100-avg) / 10 = 2 which is gradePoint
and you are returning gradePoint % 10
that means 2 % 10
which is returning 2. and it is working perfectly. Where is the issue?