Número

Overview

Spanish uses the period (.) to separate thousands. The comma (,) is used to indicate decimals. Other commonly used quantitative expressions include:

Tens

The numbers from $0$ to $29$ inclusive are expressed as one word.

Numbers from $30$ through $99$ do not combine with the number in the $1$s place in the same way as $0$ through $29$. Instead, y is used as a conjunction.

When a masculine noun follows the number $21$, $31$, $41$, $51$, $61$, $71$, $81$, or $91$, the -o is dropped from uno. When a feminine noun follows a number ending in uno, the feminine form is una.

Hundreds

The number $100$ is pronounced cien. It becomes ciento if followed by any number less than itself. Spanish does not use y to connect hundreds and the following number like is done in English. For example, $110$ is ciento diez and $315$ is trescientos quince.

The numbers $200$, $300$, $400$, $500$, $600$, $700$, $800$, and $900$ agree with the noun they modify.

Thousands

The number $1000$ is pronounced mil. It does not need the indefinite article un in front of it. The plural miles is used only to refer to a large but inexact amount, the way English uses tons.

Ordinals

Ordinal numbers tenth and below precede the noun and agree in gender with the noun they describe. Primero and tercero drop the -o before a masculine noun.

When used to describe kings, queens, popes, and centurie, ordinals follow the noun they describe. Additionally, ordinal numbers exceeding tenth are formed by stating the noun and then the regular cardinal number.