Problem:
The examples in the text show a unique characteristic (think: sign convention) associated with how the PRESENT VALUE (PV) of a monetary sum (when given) should be expressed when you are solving for future value (FV) of that sum.
Required:
Question 1: What is that characteristic?
Question 2: Why should this characteristic of PV always be precisely true, and therefore meticulously and dogmatically followed, when calculating future value of a monetary sum?
Note: Provide support for your rationale.