Learn Danish: Vi gemmer pengene væk. - We hide the money away.

This is because gemmer væk is a separable phrasal verb. In Danish, when a verb and a short direction word (a particle) like væk work together, they usually split up. The object of the sentence (pengene) comes right after the main verb (gemmer), and the particle is placed after the object.

Would it be correct to say "Vi gemmer væk pengene" instead?

No, that sounds unnatural in Danish. While in English you might say "We hide away the money," Danish requires the object (pengene) to be placed between the main verb and the particle (væk).

I see pengene has the ending -ne. Is money a plural word in Danish?

Yes! Unlike English, where "money" is a singular concept, the Danish word penge is always plural. To say "the money", you add the plural definite ending -ne, giving you pengene.

Could I just say "Vi gemmer pengene" without væk to mean the same thing?

You could, but the meaning becomes a bit less specific. By itself, at gemme can mean "to hide", but it also very commonly means "to save" or "to keep" (like saving leftovers or a computer file). Adding væk specifically emphasizes putting something out of sight.