put two and two together

English

put two and two together (third-person singular simple present puts two and two together, present participle putting two and two together, simple past and past participle put two and two together)

(idiomatic) To figure something out; to deduce or discern something.
We didn't tell our friends that we were dating, but I think they put two and two together.
- 1935, Dorothy L. Sayers, Gaudy Night:
  “I say,” said Mr. Farringdon, suddenly putting two and two together, “are you the Miss Vane? The novelist . . . You are! […]”

figure out — see also connect the dots

Finnish: älytä (fi), hoksata (fi)
French: faire le rapprochement, faire le lien (fr), raccrocher les wagons (fr)
German: eins und eins zusammenzählen (de)
Greek: τα βάζω κάτω n pl (ta vázo káto)
Hungarian: nem most jött a hathúszassal, nem most lépett le a falvédőről, átlát a szitán (hu)
Norwegian:
Bokmål: legge to og to sammen (no)

Nynorsk: leggje to og to saman
Polish: dodawać dwa do dwóch impf, dodać dwa do dwóch (pl) pf
Portuguese: juntar dois mais dois
Swedish: lägga ihop två och två (sv)
Welsh: rhoi dau a dau ynghyd