put two and two together
/ˌpʊt ˈtuː ən ˈtuː təˈɡeð.ə/idiom
to guess the truth from the information you have
сопоставить факты, сложить два и два
Русский аналог: «сложить два и два»
Put two and two together and make five — сделать неверный вывод.
“When I saw them leave together, I put two and two together.”
“It didn’t take long for the police to put two and two together.”
“She put two and two together and realised he had lied.”