alguno/a vs uno/a
In lesson 2.11 - Negatives and Indefinites, an example was given as "¿Puedes prestarme algún lápiz?". I was wondering if there is an easy way to remember when to use the indefinite vs "uno/una". I understand that if there is a question of whether something exists or not, to use the indefinite ("Hay algunos lápices" - "Are there any pencils?"). However, in the example given in the lesson, I would assume that the speaker knows the person has a pencil and wants to borrow it. It seems to me that "uno" would work here as well (or maybe better?).
¡Gracias por su ayuda!
You're right. If you know the person has some pencils, you can say, "¿Puedes prestarme un lápiz?" or .... "unos lápices" if you want more than one.