# summing+up

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**Path integral formulation**— This article is about a formulation of quantum mechanics. For integrals along a path, also known as line or contour integrals, see line integral. The path integral formulation of quantum mechanics is a description of quantum theory which… …102

**180 (number)**— This article is about the number. For other uses, see 180 (disambiguation). 180 (one hundred [and] eighty) is the natural number following 179 and preceding 181. List of numbers Integers << 180 181 182 183 184 185 …103

**Tetrahedral number**— A pyramid with side length 5 contains 35 spheres. Each layer represents one of the first five triangular numbers. A tetrahedral number, or triangular pyramidal number, is a figurate number that represents a pyramid with a triangular base and… …104

**Virtual ground**— In the theory of electrical networks, a virtual ground ( or virtual earth) is a node of the circuit that is maintained at a steady reference potential, without being connected directly to the reference potential. In some cases the reference… …105

**Mental calculation**— comprises arithmetical calculations using only the human brain, with no help from calculators, computers, or pen and paper. People use mental calculation when computing tools are not available, when it is faster than other means of calculation… …106

**Cesàro mean**— In mathematics, the Cesàro means (also called Cesàro averages) of a sequence (an) are the terms of the sequence (cn), where is the arithmetic mean of the first n elements of (an). [1]:96 This concept is named after Ernesto Cesàro (1859 1906). A… …107

**Meadowlands Racetrack**— The Meadowlands Racetrack is a horse racing track at the MetLife Sports Complex in East Rutherford, New Jersey, United States. The track hosts both thoroughbred racing and harness racing. It is known popularly in the region as The Big M. [1]… …108

**Total fertility rate**— Not to be confused with birth rate. A world map showing countries by fertility rate, 2005 2010 …109

**Numerical control**— CNC redirects here. For other uses, see CNC (disambiguation). A CNC Turning Center …110

**Curvilinear coordinates**— Curvilinear, affine, and Cartesian coordinates in two dimensional space Curvilinear coordinates are a coordinate system for Euclidean space in which the coordinate lines may be curved. These coordinates may be derived from a set of Cartesian… …