The sum of two numbers is 210. determine the maximum product of these two numbers

If we take the two numbers 105 and 105, 
if we add both these numbers we get the sum of 210
105+105 = 210
and we multiply both these numbers we get the product of 11,025.
105 x 105 = 11,025
and if we take two number 104 and 106, we get the sum of 210 but if we multiply these two numbers we get the product of 11,024 that is less than 11,025.
So the maximum product of these two numbers is 11,025.

What function are you talking about?