They're both correct.

Adding = Addition

Subtracting = Subtraction

The difference between the two is that addition is a noun, whereas adding is the present progressive form (gerund) of the verb to add

Addition and Subtraction sounds a bit more educated than Adding and Subtracting does.

They're both correct.

Adding = Addition

Subtracting = Subtraction

The difference between the two is that addition is a noun, whereas adding is the present progressive form (gerund) of the verb to add

Addition and Subtraction sounds a bit more scholarly than Adding and Subtracting does. But it is not more scholarly, really.