Hundreds Thousands

In Spanish, cien is exactly 100, while ciento begins numbers from 101 to 199; larger hundreds follow a consistent pattern with forms like doscientos and trescientos. Each hundred word agrees in gender when used with feminine nouns, so you say doscientas mesas but doscientos libros.

Mil is invariant and used for 1,000; numbers above use digits or words for thousands, and un precedes millón because millions behave like nouns. Thousands can be rounded off or made precise depending on whether you say mil quinientos or un millón doscientos mil. Remember that millón takes de before a noun when specifying what is counted.

Millón and millones behave like plural nouns: use un before millón, add de before a following noun, and match millones to any number greater than one. Large amounts beyond millions use mil millones (a billion) and billón (a trillion in Spanish), so plan for those terms if you need them.

Hundreds use cien for exactly 100 and ciento plus digits for 101–199, thousands use mil without un, and millions require un before millón and de before nouns; these patterns keep large number expressions clear and natural.