Algum - singular/masculine. Ex: Você tem algum problema? Alguma - singular/feminine. Ex: Ele gosta de alguma dessas frutas? Alguns - plural/masculine. Ex: Eu tenho alguns livros sobre história. Algumas - plural/feminine. Ex: Algumas pessoas não mudam. There is also the word "algo" which means "alguma coisa" or "uma coisa" depending on the context.

I'm not sure if I understood what you meant. But I'll try to make it simple for you, ok. Algum (singular) -> Alguns (plural) = Some [Both are used with masculine words] Ex1: Vou procurar ALGUM livro para ler mais tarde. I will look for some book to read later. [The word 'livro' is masculine and it is in its singular form, therefore you have to use 'algum'.] Ex2: Eu comprei ALGUNS biscoitos para comer. I bought some coockies to eat. [The word 'biscoitos' is masculine and it is in its plural form, therefore you have to use 'alguns'.] Alguma (singular) -> Algumas (plural) = Some [Both are used with feminine words.] Ex1: Meu avô estava falando sobre ALGUMA doença que ele teve na infância. My grandfather was talking about some disease he had in his childhood. [The word 'doença' is feminine and it is in its singular form, therefore you have to use 'alguma'. ] Ex2: Eu tenho tirado ALGUMAS fotos de casas que pretendo comprar. I have taken some pictures of houses I intend to buy. [The word 'foto' is feminine and it is in its plural form, therefore you have to use 'algumas'.] *I think you already know this, but anyway. Although fotO ends with an O, it is a feminine word. * the word 'any' also means algum, alguma and other things in Portuguese. But it's a whole different story. to summarize, 'some' in Portuguese means algum, alguns, alguma, algumas and other things.

You have to know that different from the English language, Portuguese adjectives when describing nouns that are in plural also need a plural form. Example: Algumas casas - Some houses Alguns mercados - Some markets Lugares coloridos - colorful places Sapatos amarelos - yellow shoes

Não sei se entendi o que quis dizer, mas algum e alguma não estão no plural, quer dizer uma única coisa. Exemplo:"Eu comprei alguma coisa para o jantar". Alguns e algumas, sim estão no plural.