Zero: The Biography of a Dangerous Idea

by Charles Seife

Brahmagupta tried to figure out what 0 ÷ 0 and 1 ÷ 0 were, and failed. “Cipher divided by cipher is naught,” he wrote. “Positive or negative divided by cipher is a fraction with that for a denominator.” In other words, he thought 0 ÷ 0 was 0 (he was wrong, as we will see), and he thought that 1 ÷ 0 was, well, we don’t really know, because he doesn’t make a whole lot of sense. Basically, he was waving his hands and hoping that the problem would go away. Brahmagupta’s mistake did not last for very long. In time the Indians realized that 1 ÷ 0 was infinite. “This fraction of which the denominator is a cipher, is termed an infinite quantity,” writes Bhaskara, a twelfth-century Indian mathematician, who tells of what happens when you add a number to 1 ÷ 0. “There is no alteration, though many be inserted or extracted; as no change takes place in the infinite and immutable God.” God was found in infinity—and in zero.