Cardinal and Ordinals numbers

1. Cardinal numerals. Cardinal numbers or numerals (1, 2, 3, etc.) may be used as adjectives or pronouns. The most common ones are:
   

   0	cero		10	diez		20	veinte		30	treinta
   1	un, uno, una		11	once		21	veintiuno/a		31	treinta y uno/a
   2	dos		12	doce		22	veintidós		32	treinta y dos
   3	tres		13	trece		23	veintitrés		33	treinta y tres
   4	cuatro		14	catorce		24	veinticuatro		34	treinta y cuatro
   5	cinco		15	quince		25	veinticinco		35	treinta y cinco
   6	seis		16	dieciséis		26	veintiséis		36	treinta y seis
   7	siete		17	diecisiete		27	veintisiete		37	treinta y siete
   8	ocho		18	dieciocho		28	veintiocho		38	treinta y ocho
   9	nueve		19	diecinueve		29	veintinueve		39	treinta y nueve

   
   

   40	cuarenta		100	cien/ciento		700	setecientos		1.000.000	un millón
   50	cincuenta		200	doscientos		800	ochocientos		2.000.000	dos millones
   60	sesenta		300	trescientos		900	novecientos
   70	setenta		400	cuatrocientos		1000	mil
   80	ochenta		500	quinientos		1001	mil uno
   90	noventa		600	seiscientos		2000	dos mil

   Note:
   
   1. Three-word forms also exist for most numbers between 16 and 29: diez y seis, veinte y tres.
   2. Numbers such as 1999 must be expressed as mil novecientos noventa y nueve (not nineteen hundred ninety-nine).
   3. Numbers ending in “one” have feminine singular forms when used with feminine nouns: veintiuna mujeres, cincuenta y una pesetas.
   4. NEVER USE *un mil.
   5. De is used between millón and a noun being counted: un millón de dólares, cien millones de habitantes.
   6. In writing out Spanish numerals, commas are used were we use periods in English, and periods instead of commas: 1.240,5 (= 1,240.5).
2. Ordinal numbers indicate the order in which something occurs (first, second, etc). There are forms form almost all numerals, but in normal practice all you will use are the forms for the numbers one through ten. Remember that these are adjectives and agree with the noun modified. The forms primer and tercer are used only before masculine singular nouns.
   

   1°	primer, primero		6°	sexto
   2°	segundo		7°	séptimo
   3°	tercer, tercero		8°	octavo
   4°	cuarto		9°	noveno
   5°	quinta		10°	décimo

   
   

   
   

   Ésta es mi primera clase universitaria.		This is my first college class.
   No puedo entender el tercer párrafo.		I can't understand the third paragraph.

   Note that we used after names such as “Charles the Fifth”, the word “the” is not used before the ordinal: Carlos V = Carlos Quinto; Felipe II = Felipe Segundo.