According to the Miriam-Webster dictionary calculus is a method of computation or calculation in a special notation (as of logic or symbolic logic). It is the field of mathematics that analyzes aspects of change in processes or systems that can be modeled by functions. Through its two primary tools—the derivative and the integral —it allows precise calculation of rates of change and of the total amount of change in such a system. The derivative and the integral grew out of the idea of a limit, the logical extension of the concept of a function over smaller and smaller intervals. The relationship between differential calculus and integral calculus (modern calculus), known as the fundamental theorem of calculus, was discovered in the late 17th century independently by Isaac Newton and Gottfried Wilhelm Leibniz. Calculus was one of the major scientific breakthroughs of the modern era. The first evidence of calculus can be traced back to ancient Egypt where calculations of volumes and areas, a goal of integral calculus, were found recorded on papyrus from circa 1820 BC. Greek mathematicians Eudoxus and Archimedes developed a precursor to the limit that calculates areas and volumes in the period circa 287-212 BC. In China in the 3rd century AD Liu Hui used a method similar to limits to find the area of a circle and later in the 5th century AD Zu Chongzhi established a method that could be used to find the volume of a sphere.
If Calculus didn’t exist the world wouldn’t just be different it would be unrecognizable. Without calculus, we would not be able to