What gender and number agreement in Spanish?

In Spanish, gender and number agreement refers to the way adjectives, articles, and nouns must match in gender (masculine or feminine) and number (singular or plural). For example, a masculine singular noun like "niño" (boy) would use the masculine singular article "el," while a feminine singular noun like "niña" (girl) would use "la." In the plural, "niños" (boys) pairs with "los" and "niñas" (girls) with "las." This agreement is crucial for grammatical accuracy in the language.