Translation:You ask her to learn numbers.
You are totally right about songs being a correct translation. However, let me explain this a bit. "Nummers" literally means "numbers". "Songs" would be correctly translated to "Liedjes" or "Liederen" (first one is more commonly used).
This is a case of "accepted" informal language. It derived from the fact that (for example) CD's contain a bunch of songs indicated by a number. That's why Dutch people also use the term "nummers" to indicate songs.
Older people who were used listening to LP records when they were younger sometimes refer to a "song" as a "plaat". This is because "LP record" translates to "langspeelplaat" in the Dutch language. The term "langspeelplaat" was shortened to "plaat" in the spoken language and thus we Dutch people refer to "songs" with three different terms, "liedjes" or "liederen" being the literal one.
Btw, "a song" translates to "een lied". And "een liedje" would actually mean "a little song".
Excuse me, I'm terribly sorry that I just told you that you are correct about the translation. I'm also sorry I gave you a little history lesson about my language.
But I'm upmost sorry I just mixed up the terms "slang" and "informal". I edited it right away, I hope we can both sleep well again.
"Ask" CANNOT be exchanged for "request" in all cases in English. For example: I ask her to learn numbers... OK I request her to learn numbers... NOT OK (but Duo currently accepts this) I request that she learn numbers... OK