Addition

Addition is the name given to the mathematical function which involves the combination of two values, resulting in a directly related linear increase. The sum a + b can be interpreted as a binary operation that combines a and b, in an algebraic sense, or it can be interpreted as the addition of c more units to b. Under the latter interpretation, the parts of a sum c + a play symmetric roles, and the operation a + c is viewed as applying the unary operation +b to a. Instead of calling both a and b addends, it is more appropriate to call a the augend in this case, since a plays a passive role. The unary view is also useful when discussing subtraction, because each unary addition operation has an inverse unary subtraction operation and vice versa.

Examples:

3 + 2 = 5 the order of the operands doesnt matter 3 + 2 = 2 + 3 = 5
for larger numbers they are added in order of smallest unit to largest unit
17 + 25 = 42 add the units 5 + 7 = 12 add the tens 10 + 20 = 30 then add them 12 + 30 = 42