Hi Tracy, Often, both can be used interchangeably, meaning an indefinite number. However, this is not always the case, and can express subtle differences. You may find this article of interest, it is explained very well. www.thoughtco.com/algunos-vs-unos-3079685 Good study, Rocio

Tengo algunos amigos que son médicos (varios pero no me refiero a ninguno en especial) Tengo unos amigos que son medicos (tengo en mi mente cuales son) Este es uno de los usos........

There is no big difference, but it also depends on the object, which signals, for example, saying I want some tennis shoes, it is understood as a pair of tennis shoes, singular, but if you say I want some sweets it is understood as several, basically with the word ones, you can point, one or several, and with some, you can only point several, that is, in the plural

Yes! I’d say “unos” is used as “some”. Now, “algunos” is something like “several”, it’s like you could count them. They are quite interchangeable.

Por ejemplo; Yo tengo “ unos “ pocos plátanos. Yo tengo “ algunos “ plátanos. Cualquiera de las dos palabras te sirven, es como decir que tienes plátanos pero no mucha cantidad de plátanos.