In Arithmetic, addition operation involves two or more numbers and an addition operator i.e (+)
When two numbers(1 and 2) are added, their sum is indicated as 1 + 2.

For Example = Show addition operation on the following pair of numbers.
(12, 3) = 12 + 3
(189, 90) = 189 + 90
(15, 2, 47) = 15 + 2 + 47
(109, 901, 1, 47) = 109 + 901 + 1 + 47

In algebra, addition operation involves two or more literal numbers and an addition operator i.e (+)
When two literal numbers(a and b) are added, their sum is indicated as a + b.

For Example = Show addition operation on the following pair of literal numbers.
(a, b) = a + b
(f, g) = f + g
(x, y, z) = x + y + z
(p, q, r, s) = p + q + r + s