Hola Daria, In the examples that you suggest I would translate "unas" as "a few." It would work perfectly. The difference between "some" and "a few" is only a matter of what you are trying to convey.

If you "unas" before a number, it means "about or approximately." There is a lesson on this in Kwiziq (pasted below) where they also suggest that it can be translated as "some," but I can't find an example for that anywhere. I wonder would it be something like " Here are some (unas) €2 coins," or "There are some (unas) 40 minute slots available on table tennis tables this afternoon," but I am only guessing. Saludos. John

Using unos, unas + number = about/approximately%252Fsearch%253Fs%253Dunas