Right, and I addressed all that as well. I doubt we are in serious disagreement here and calls for me to “read a book” are frankly rude. I think you need to be more generous in the interpretation of others words because I actually disagree with the original poster for the most part, but you obviously have a different definition of “teach” than he. Flash cards don’t teach. They assist memorization or practice. Memorizing times tables doesn’t teach multiplication except trivially for the numbers you’ve memorized. It does assist in learning multiplication. Likewise this ear training can trivialize learning and identifying intervals later but is not itself “teaching intervals”.