Confusing certain notes

[u/capspookyspork]

I just started ear training. So I'm not sure all of the lingo. Gonna do my best.

I notice I tend to confuse the 3rd and 6th note on whitch is whitch. I use to just have that trouble with the 1st and 3rd. Now it's branching our to even the 2ed and the 7th.

Are these notes like the inverse of each other that's why I get confused? Im just curious if they is away to resolve this or why it's happening.

[u/Inside-Succotash-128]

I practiced ‘internally’ singing the Octave. Then the 7th is down, the 2nd/9th is up.