Code Challenges: Javascript Fundamentals Code challenge 5

What is wrong with this code, when I average the thee grades there is a syntax error

// Write your function here:
const finalGrade = (midterm, final, homework) => {
(midterm + final + homework) / 3);
if ((midterm < 0 || midterm > 100) || (final < 0 || final > 100) || (homework < 0 || homework > 100)) {
return (‘One or more than one of your grades is invalid.’);
} else if (averageGrade <= 59) {
return ‘F’;
} else if (averageGrade <= 69) {
return ‘D’;
} else if (averageGrade <= 79) {
return ‘C’;
} else if (averageGrade <= 89) {
return ‘B’;
} else if (averagegrade <= 100) {
return ‘A’;
} else {
return (‘One or more than one of your grades is invalid.’);
}
}

// Uncomment the line below when you’re ready to try out your function
console.log(finalGrade(99, 92, 95)) // Should print ‘A’

// We encourage you to add more function calls of your own to test your code!

Hello @ac_hu. Where do you store the values of this:

You reference averageGrade, but I don’t see where that is defined.