Meaning of perfect numbers. A perfect number: a number is perfect when the sum of its divisors (except the number itself) equals the given number. Theorem connecting perfect and prime numbers. 6 : The divisors of 6 are 1,2,3 & 6.
Â­A watershed is an area of land that feeds all the water running under it and draining off of it into a body of water. It combines with other watersheds to form a network of rivers and streams that progressively drain into larger water areas. Topography determines where and how water flows.Ridge tops surrounding a body of water determine the boundary of a watershed. Imagine turning an open umbrella upside down in the rain.he umbrella is like a watershed; it collects everything that falls into it. Waterways within the watershed all feed into that main body of water, which could be a river, lake, or stream. The beginnings of a water source are called headwaters.
Watersheds are defined by the way water flows across the land and are shaped by features and elevations on the surface of the land. Springsheds, on the other hand, are defined by the way water flows beneath the land and are shaped by the geology and pressure below the surface of the land. watershed is an area of land that water flows across as it moves toward a common body of water, such as a stream, river, lake or coast.