Hmm, let's see. Some games that haven't been mentioned yet.
Operation Neptune You're in a submarine, navigating puzzles and solving math problems. There's an ongoing story and you can change the difficulty at any time (the difficulty of the math problems). You had ammo for some ink gun that you could use to stun the enemies and I remember it being very colourful, even for EGA. This was a popular one at my school.
Word Rescue It gives you a word to spell and you have to collect the letters in order. Pretty fun platformer with some simple enemies and other stuff. This one's pretty easy though and was intended for a young audience.
Math Rescue This one is harder than Word Rescue. You can fine tune the difficulty of it I think. It's also more colourful and has better backgrounds.
Treasure Mountain This one was the best. You have to climb up a mountain (which is divided into three sections and get to the top. To do that you need to catch these little elves in a net and if you catch one that's carrying a scroll you get a simple word or math problem with a multiple choice selection for the answers. Once you solve it you get a clue word. When you get enough clue words you can then search the features of that section for the key to get to the next level. There's a ladder puzzle you have to solve when you reach the top and if you can beat it you're rewarded with a treasure which gets added to your stash at the bottom of the mountain.
My brother, sister, and I played the hell out of this game when we were kids. It's really fun.
Reader Rabbit This one was aimed at a younger audience and I never really played it but my sister loved it (she's four years younger than me)
Then of course there's the standards of Cross Country Canada and Where in the World is Carmen Sandiego but those have been mentioned already. I think I'm forgetting a few but it's been a long time since the days of elementary school so I don't know if I can remember anything else.