Addition

Addition

Addition is the operation which produces the sum of two (or more) numbers. The order of addition does not affect the result.
There is a number 0, called zero, such that the sum of any number a and zero is a.
Corresponding to each number a, there is a number (-a), called the opposite of a, such that the sum of a and (-a) is zero.
Also, for any two numbers a, b there is a unique number x such that a + x = b, namely, x = b + (-a), more commonly written x = b - a.
A set with an addition law satisfying the above properties, and such that all sums lie in the set, is called an additive group. [RA] {EB}