The sum of two numbers is what we get when we add the two numbers together. This operation is called summation. There are a number of ways of writing sums, with the most common being:
- Addition ()
- Summation ()
- Sum = 0
- For I = M to N
- Sum = Sum + X(I)
- Next I (in Visual BASIC)
Sigma notation is a mathematical notation to write long sums in a short way. Sigma notation uses the Greek letter Sigma, (∑), and takes upper and lower bounds which tell us where the sum begins and where it ends. The lower bound usually has a variable (called the index) given a value, such as "i=2". This tells us that the summation begins at 2, and goes up by 1 until it reaches the number on the top.
The geometric series of a repeating decimal can be represented in summation,
The concept of an integral is a limit of sums. The area under a shape being defined as:
Sum Facts for Kids. Kiddle Encyclopedia.