Sum

 A sum is simply calculated. Arithmetic calculation is performed in determining the sum. Calculation of sum is part of elementary mathematics. Addition is performed for finding the sum.

When Sum is to be found, we must have a minimum of two numbers. When two numbers are added, we get the Sum of two numbers. As for example,

4 + 5 = 9

'4' is the augend. '5' is the addend. '9' is the Sum. The arithmetic operator '+' is used. 

We can have a Sum of more than two numbers. There is no upper limit on the count of operands in calculation of Sum. The minimum count of numbers to be added is two. 

In the addition of numbers, we calculate the Sum of parts. The total Sum cannot be more than the values of the individual parts. Similarly, the total Sum cannot be less than values of individual parts. So, we can say that the  Sum concept proves the truthfulness and durability of numbers.

The Sum tells about the magnitude of individual parts. In this way we can say that the Sum is an abstraction of the parts. Parts are processed to produce the Sum. 

The successful calculation of Sum of numbers expresses the commitment of the involved numbers to produce the result.

When we count numbers,  actually we perform addition. As we count, we go on producing successive numbers. As we count '1' is added to the preceding number leading to the following number. As for example, suppose '1' is the starting number. When '1' is added to '1' ( starting number), we get '2'. '1' comes before '2', or '1' precedes '2'. In other words, '2' follows '1'. We saw how we got '2'. 1, 2, 3, 4, ...... is a series of successive numbers.

The Sum of two even numbers is an even number ( 4 + 8 = 12 ). The Sum of two odd numbers is an even number ( 7 + 5 = 12 ). The Sum of an even number and an odd number is odd ( 2 + 7 = 9).