Some of the improvement was probably age-related brain growth. I noticed in high school and college that as I got older, my performance on repeated math tests

Some of the improvement was probably age-related brain growth. I noticed in high school and college that as I got older, my performance on repeated math tests or contests mysteriously improved, even if I didn't do any practice in between. Math problems that seemed out of my reach suddenly became attainable. Some friends of mine noticed the same thing when I pointed it out to them.