That's true in a very literal sense, but there's a whole branch of linguistics called pragmatics that's concerned with things like why it's usually safe to conclude that when someone says they have four apples, they mean that have only four apples. When there's any ambiguity I talk like a mathematician and use phrases like "at least four apples" or "exactly four apples".

It's technically correct, like saying at least 4 people died from covid.

OP treating his statement as a correction requires that he’s not using this interpretation. If he were to use this defense, so could the teacher, so he’d just be changing how he’s wrong, not that he is.

What if there's a worm in one of them?

Like, you think you habe more than four apples.

Then you find out that most of them have worms.

In the end, you are left with two apples.

So now, it is not true that you have four apples.