Números y la hora
Today: numbers from 0 to 100 and how to tell time. Spanish numbers don't have weird agreement rules — but 16-29 are written as one word, and from 31 up they're joined with y.
0–15 — memorize
0 cero, 1 uno, 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. uno has shortened forms: un (m.), una (f.) — un libro, una casa.
16–29 — one word
16 dieciséis, 17 diecisiete, 18 dieciocho, 19 diecinueve. 20 veinte. 21 veintiuno (or veintiún before a masculine noun), 22 veintidós, 23 veintitrés, 24 veinticuatro… 29 veintinueve. Originally 'diez + y + …' and 'veinte + …', now just glued together.
30–99 — split with 'y'
Tens: 30 treinta, 40 cuarenta, 50 cincuenta, 60 sesenta, 70 setenta, 80 ochenta, 90 noventa. Between the tens and the units, use y: 31 treinta y uno, 45 cuarenta y cinco, 78 setenta y ocho. Three separate words.
100 and beyond
100 cien (exactly one hundred — cien), but 101 ciento uno, 200 doscientos, 500 quinientos, 1000 mil. cien becomes ciento before any other number: cien casas but ciento veinte casas.
Time: '¿Qué hora es?'
The question is singular ('what hour is it'), but the answer is almost always plural: Son las tres (it's 3 o'clock). Exception: 1 o'clock is singular: Es la una (it's 1). Minutes past: Son las tres y diez (3:10). Half past: Son las tres y media (3:30). Before: Son las tres menos cuarto (quarter to 3 = 2:45).
Morning, afternoon, evening
de la mañana = AM (after midnight). de la tarde = afternoon (after noon). de la noche = evening / night. Las ocho de la mañana = 8 AM. Las nueve de la noche = 9 PM. a las… = at…: ¿A qué hora? (at what time?), A las siete (at seven).
