Addition can be explained as the mathematical operation of calculating the sum of two or more integers. The symbol for addition is '+', and the number to be added are called addends. The results of the addition is called the sum. The order doesn't matter in the case of addition. The sum 4+10 and 10+4 are the same. Since the order that we add things doesn't matter, we say that the addition is commutative. This online addition calculator is used in add positive integer and negative integer to give grand total. 

The sum of two numbers 84 and 57 is?

Solution:
The Sum of Two Numbers

Step 1. 
             Adding 7 + 4 = 11 (Reminder is 1)
Step 2.
             Carry 1 + 8 + 5 = 13

Answer: The sum of 84 and 57 is 131.