I played some games as a kid a long time ago that were 2D 8-bit/16-bit platformers designed to help practice basic skills like either spelling or arithmatic.
You could play as either a boy or a girl and you were helped by a "bookworm" mentor that had butterfly wings (also arms and hands). When you encountered an enemy, you would see a prompt for the word or equation you need to input the missing letter or number for and, if yu get it right, the bookfly/butterworm wpuld appear and dump a bucket of pink slime over the enemy to neutralize it.
Some of the environments included a medieval castle and some underwater areas. I don't remember much else than that. Well, actually, two things I remember was it used my computer's onboard speaker (the really tinny chiptune soinsing one) for sound effects and that the MC's idle animation had this funny/awkward loop of the boy or girl shifting their head to the right and then to the left while looking at the camera.

I'm guessing it's from the '90s, but searching keywords like "pink slime" and "bookworm" and stuff didn't seem to help. I really want to play them again. Any help would be appreciated, anons.