Im just learning Excel and Its been fine up to this one formula. As much as I do it I cant seem to figure out what I'm doing wrong so maybe someone here can help me?

=IF($L5>=0.9, “A”, IF(AND($L5>=0.8, $L5<0.9), “B”, IF(AND($L5>=0.7, $L5<0.8), “C”, IF(AND($L5>=0.6, $L5<0.7), “D”, “F”))))

Thanks.