The end page of SING THE NUMBERS 1 lists several things we can do as “next steps” - which I take to mean after we find that following the initial set of exercises is leading to “mindless practice” where our mind is not fully engaged. (Took me 2+ months to get to that point).
Here’s some ways I’ve tried to extend the Sing the Numbers exercises so that I don’t do mindless practice:
Do the Sing the Numbers exercise as instructed, sing back what the track just sang, but also sing another note or two before the track sings the next segment. This makes me think and feel a little more deeply.
Write down the note sequences on a piece of paper for a track, and then “flip the exercise” by singing the numbers in the empty space BEFORE the next segment. So instead of hearing the track segment and singing that afterwards, sing the next sequence coming up and let the track confirm you got it right. That is, if the next track sequence is 5-6-3, sing that, and let the track sing it back to you.
Using the same piece of paper from above, sing some the sequences over the IFR backing tracks, changing key each time you do it. I find this to be a completely different experience than singing back the numbers - I actually have to aurally visualize the sounds more clearly.
Get a list of children song (like from here on the Internet https://us.napster.com/artist/the-countdown-kids/album/100-favorite-kids-songs) and see if you can sing the numbers to the first phrase or two of different songs. If you get muddled and want to throw up your hands, search the internet for the sheet music of the song and see where you’ve gone off track.
I’d be interested in other ways others have found to extend SING THE NUMBERS.