LOS NUMEROS
1. uno (un & una before nouns)
2. dos
3. tres
4. cuatro
5. cinco
6. seis
7. siete
8. ocho
9. nueve
10. diez
11. once
12. doce
13. trece
14. catorce
15. quince
16. diez y seis (or – dieciséis)
17. diez y siete (or – diecisiete)
18. diez y ocho (or – dieciocho)
19. diez y nueve (or – diecinueve)
20. veinte
21. veinte y uno (or – veintiuno)
22. veinte y dos (or – veintidós)
23. veinte y tres (or – veintitrés)
24. veinte y cuatro (or – veinticuatro)
25. veinte y cinco (or – veinticinco)
26. veinte y seis (or – veintiséis)
27. veinte y siete (or – veintisiete)
28. veinte y ocho (or – veintiocho)
29. veinte y nueve (or – veintinueve)
30. treinta
31. treinta y uno
32. treinta y dos
33. treinta y tres
40. cuarenta
41. cuarenta y uno
42. cuarenta y dos
50. cincuenta
60. sesenta
70. setenta
80. ochenta
90. noventa
100. cien, ciento
101. ciento uno
102. ciento dos
103. ciento tres
110. ciento diez
199. ciento noventa y nueve
200. doscientos
201. doscientos uno
202. doscientos dos
203. doscientos tres
251. doscientos cincuenta y uno
252. doscientos cincuenta y dos
300. trescientos
400. cuatrocientos
500. quinientos
600. seiscientos
700. setecientos
800. ochocientos
900. novecientos
1.000. mil
2.000. dos mil
3.000. tres mil
3.333. tres mil trescientos treinta y tres
1,000,000. un millón
1,000,000,000. mil millones
Shortening uno and ciento: Uno and numbers ending in -uno are shortened to un when they immediately precede a masculine noun. When standing alone (that is, being 100 exactly) ciento is shortened to cien before preceding a noun of either gender; the longer form is used within longer numbers (except when preceding mil).
Examples: un lápiz (1 pencil), una pluma (1 pen), cincuenta y un lápices (51 pencils), cincuenta y una plumas (51 pens), cien lápices (100 pencils), cien plumas (100 pens), ciento tres lápices (103 pencils), ciento tres plumas (103 pens), cien mil lápices (100,000 pencils), cien mil plumas (100,000 pens)
Gender: As indicated above, the italicized portions of numbers vary according to gender. When a number ends in -uno ("one"), the form -un is used before masculine nouns, and -una before feminine nouns. The uno form is used only in counting. Accent marks are used where needed to maintain the correct pronunciation. The hundreds portions of numbers change in gender even when other parts of the number intervene before the noun.
Examples: un coche (1 car), una casa (1 house), veintiún coches (21 cars), veintiuna casas (21 houses), doscientos coches (200 cars), doscientas casas (200 houses), doscientos dos coches (202 cars), doscientas dos casas (202 houses).
Punctuation: In most of the Spanish-speaking world, periods and commas within numbers are reversed from what they are in U.S. English. Thus in Spain 1.234,567 would be the way of writing mil doscientos treinta y cuatro coma quinientos sesenta y siete, or what would be written in the United States as 1,234.567. In Mexico, Central America and Puerto Rico, numbers usually are punctuated as they are in the United States.