"Les trois mois de l'hiver sont" means "The three months of winter are", or, if it was a question, the answer is "décembre, janvier, février".
Trois in French is "three" in English.
'le trois juillet'
"Three truffles" is an English equivalent of the French phrase trois truffes. The pronunciation of the masculine plural phrase will be "twah tryoof" in French.
"My three sons" in English means mes trois fils in French.
"Are there three floors?" is an English equivalent of the French phrase Est-ce qu'il y a trois étages? The question translates literally into English as "Is this that it has there three stories?" The pronunciation will be "eh-skee-lya twa-ze-tazh" in French.
"That makes three daughters!" is an English equivalent of the French phrase Ça fait trois filles! The observation also translates literally as "That makes three girls!" in English. The pronunciation will be "sa feh twa fee" in French.
Trois cent quinze and Trois heures quinze are French equivalents of the English number "315." Context makes clear whether number (case 1) or time (example 2) suits. The respective pronunciations will be "twa saw kehz" and "twa-zur kehz" in French.
"Trois mois" means "three months" in English.
"The three months of the..." is an English equivalent of the incomplete French phrase les trois mois de l'. The masculine plural phrase also translates into English as "three months of the..." since English does not employ "the" every time that French uses definite articles -- les and l', in this case. The pronunciation will be "ley twa mwa duh luh" in French.
"Three billion (3,000,000,000)" is a literal English equivalent of the French phrase trois milliards. The pronunciation of the masculine plural numerical phrase -- which most famously references the movie Trois milliards sans ascenseur ("Three billion without [an] elevator") directed by French actor / producer Roger Pigaut (April 8, 1919 - December 24, 1989) in 1972 -- will be "twa mee-lyar" in French.
"Eighty-three (83)" is an English equivalent of the French word quatre-vingt-trois. The pronunciation of the compound plural noun -- which translates literally by word order as "four twenty (twenties plus) three" -- will be "kat-veh-twa" in northerly French and "ka-truh-veh-twa" in southerly French.
"The number 3 has a green door" is a literal English equivalent of the French phrase Le numéro trois a une porte verte. The pronunciation of the declarative statement will be "luh nyoo-mey-ro twa yoon port verte" in French.