Final answer:
The equation f = D + A is a mathematical problem involving addition of two variables, D and A, to find the value of f.
Step-by-step explanation:
The equation f = D + A is a mathematical problem involving addition of two variables, D and A, to find the value of f. In this equation, D and A represent numbers or quantities, and the addition operation combines them to give the value of f. For example, if D = 5 and A = 3, then the value of f would be 8.