There are several idioms formed with numbers. Check them out!

Cero

ser un cero a la izquierda - to be useless

Uno

una y no más, Santo Tomás - once is enough

Dos

cada dos por tres - very frequently
estar entre dos fuegos - to be caught in the crossfire
estar entre dos aguas - to sit on the fence
estar a dos velas - to be without something (money, sex)
como dos y dos son cuatro - as sure as eggs is eggs

Tres

dar tres cuartos al pregonero - to let a secret out
buscar tres pies al gato - to make things more complicated than they are
donde Cristo dio las tres voces - in a very distant, solitary place
A la tercera va la vencida - third time lucky
Ni a la de tres - Nothing doing!
no ver tres en un burro - to see nothing (because it is so dark)

Cuatro

echar un cuarto a espadas - to intervene, give an opinion
estar a la cuarta pregunta – to be pennyless
Estaban/había cuatro gatos. - There were very few people ther

Cinco

Choca esos cinco - Give me five!

Siete

hacerse un siete en la ropa - to have a tear your clothes
estar en el séptimo cielo - to be in seventh heaven
andar/recorrer las siete partidas - to keep going over (an idea)
tener siete vidas - to have nine lives
pícaro de siete suelas - helluva rascal

Diez

hacer las diez de últimas - to end up with nothing

Once

meterse en camisa de once varas - to poke your nose in (where it is not your concern)

trece
mantenerse en sus trece - to stick to your guns
martes y trece - Tuesday the thirteenth (considered an unlucky day, like Friday the thirteenth in the English-speaking world)

Cuarenta

cantarle las cuarenta - to give someone a piece of your mind

Cien

poner a uno a cien - to (cause to) get in a state of high excitement
Dentro de cien años todos calvos. - in the future it won’t matter

Mil, millón

Mil gracias /Un millón de gracias - Many thanks
Vendrá a las mil quinientas. - He’ll come well beyond the agreed time.

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