JavaScript Credit Card Checker Problem

Hey guys,

I am working through the credit card checker exercise and I’m confused as to why my code isn’t working for step number 3. I am just testing the sum value because it should add up to 100 but it isn’t. Any help would be greatly appreciated.
Exercise: https://www.codecademy.com/paths/full-stack-engineer-career-path/tracks/fscp-javascript-syntax-part-ii/modules/fecp-challenge-project-credit-card-checker/projects/credit-card-checker

My solution:

const validateCred = arr => {
let sum = 0;
let doubleSum = 0;
let reversedArr = arr.reverse();
for (let i = 0; i < reversedArr.length; i++){
let multiply = reversedArr[i];
if (i % 2 ===0 && i !== 0 && multiply * 2 < 10) {
sum += multiply * 2;
} if (i % 2 ===0 && i !== 0 && multiply * 2 > 10) {
sum += ((multiply * 2) - 9)
//console.log(sum)
}
if (i % 2 !== 0) {
sum = multiply + sum;
//console.log(multiply)
//console.log(sum)
} if (i == 0) {
sum += multiply;
//console.log(sum)
}
//console.log(sum)
//console.log(reversedArr[3] * 2)
}
}