The Institute of Mathematics of the Romanian Academy is located in Bucharest, Calea Griviței 21, very close to the famous Calea Victoriei.
By Plane
Bucharest is close to the Henri Coandă Airport, located 20 km to the North of the city.
From airport to Bucharest
If you come by airplane, from the Henri Coandă Airport you can take the shuttle bus 100 up to Piața Romană (recommended). You can pay by card in the bus, or you may buy a card in the airport and charge it with some tickets.
Alternatively, you can take a taxi cab (the price may vary between 12 to 20 euro).
Alternatively, you may take the train from the airport to the North Train Station, then the metro, change at Piața Victoriei to Piața Romană, and then it is a walking distance. For the metro you have to buy magnetic cards with 2 or 10 tickets either from the vending machines or from the operator (if open).
Train
If you come by train, from the North Train Station you can take the metro and change at Piața Victoriei to Piața Romană, and then it is a walking distance.