Mathematics can even be a matter of life or death.
During the Russian revolution, the mathematical physicist Igor Tamm was seized by anti-communist vigilantes at a village near Odessa where he had gone to barter for food. They suspected he was an anti-Ukranian communist agitator and dragged him off to their leader. Asked what he did for a living he said that he was a mathematician. The sceptical gang-leader began to finger the bullets and grenades slung around his neck. Tamm slowly calculated the answer in the dust with his quivering finger.