The second part of the conversation between socrates and meno is about meno not knowing the difference between learning and recollecting.Socrates use a slave to help meno understand the differences between these 2 things by asking and impling questions to the slave about a math problem in which he tries to explain the solution without  knowing the right answer.

So: Now, if this side were two feet and this side two feet also, how
many feet would the whole be? Look at it like this: if this one were two feet
but this one only one foot, wouldn’t the area have to be two feet taken once?
Slave: Yes.
So: When this one is also two feet, there would be twice two?
Slave: There would.
So: An area of twice two feet?
Slave: Yes.
So: How much is twice two feet? Calculate and tell me.
Slave: Four, Socrates.
So: Couldn’t there be one different from this, doubled, but of the
same kind, with all the lines equal, as in that one?
Slave: Yes.
So: And how many feet in area?
Slave: Eight.
So: Come then, try to tell me how long each line of this one will be.
Meno 12
In that one, it’s two, but what about in that doubled one?
Slave: It’s clearly double, Socrates.

Then after some questions meno understands the different characteristics fo recollection and learning by hearing that the boy gave a wrong answer at the end.

So: You see, Meno, that I am not teaching anything, but put
everything as a question. He now believes he knows what sort of line the
eight feet area comes from. Or don’t you think so?
M: I do.
So: And does he know?
M: Not at all.
So: He believes it comes from the double?
M: Yes.