"One of the greatest contributions to modern mathematics, science, and engineering was the invention of near the end of the 17th century," says The New Book of Popular Science. Without the invention of , many technological accomplishments, such as the landing on the moon, would have been difficult. The word "calculus" originated from the Latin word meaning pebble. This is probably because people many years ago used pebbles to count and do arithmetic problems. The two people with an enormous contribution to the discovery of the th ....