From the solstice in the summer of 1665 to the spring of 1667, Newton made a breakthrough in the study of calculus during his escape from the plague in his hometown. 1665, 165438+ 10. In October, he invented the downstream counting method (differential method) and established the counter-current counting method (integral method) in May of the following year. In the month of 1666+00, Newton compiled the research results of the previous two years into a summary paper-A Brief Discussion on Flow Number, which is also the first systematic calculus document in history, marking the birth of calculus.