In Spanish, adjectives must agree with the noun in gender (masculine / feminine) and number (singular / plural). That means: If the noun is masculine, the adjective is masculine If the noun is feminine, the adjective is feminine If the noun is plural, the adjective is plural Look at these examples: el bolígrafo rojo → the red pen la carpeta roja → the red folder los bolígrafos rojos → the red pens las carpetas rojas → the red folders You can see how rojo → roja → rojos → rojas changes to match the noun. The same happens with other colors and adjectives: verde → el bolígrafo verde / la carpeta verde / los bolígrafos verdes azul → el bolígrafo azul / las carpetas azules So remember: 👉 Noun changes → adjective changes too.