Curta is a portable mechanical calculator. It can be used for addition, subtraction, multiplication and division. Designer of Curta was Curt Herzstark (1902-1988). He was half-Jewish and was interned during WW2 in the Buchenwald concentration camp. In 1938 he had been issued a patent for a calculator and was allowed to continue his work in the camp. He survived the war and founded a company producing Curta calculators. About 140 000 calculators were made. Production ceased in 1972.