¡Hello Anjman! In Spanish the colours can be used as nouns or as adjectives. When you use them as nouns, the gender is always masculine: "el rojo, el azul, el amarillo, ...". When you use them as adjectives the gender changes depending on the noun they describe: "el auto rojo, la camisa amarilla, ...". The plural form follows the same rules, if are nouns: "los rojos, los azules, los amarillos" (only if you are referring to the color itself) if are adjectives: "los autos rojos, las camisas amarillas". I hope this helps.

Some colours have gender, here the list: Colour: masc/fem red: rojo/roja yellow: amarillo/amarilla orange: naranjo/naranja pink: rosado/rosada black: negro/negra white: blanco/blanca gray: plomo/ploma (the synonymous is "gris") I hope it useful

It's like Juan saying, but it's easy to remember: In plural add "s" to final, like rojo -> rojos or amarillo -> amarillos The gender is the difficult, so i recomend you to learn first articles and then, you can know what gender is it. Remember: La -> female singular Las -> female plural El -> male singular (not to confuse with él, pronoun) Los -> male plural (but can be used for objects, ex. Los árboles)