Refresher on Net Present Value

Something I learned long ago.  But we can use a revisit of basic economics.  Nicely presented in the HBR.

" ... Most people know that money you have in hand now is more valuable than money you collect later on. That’s because you can use it to make more money by running a business, or buying something now and selling it later for more, or simply putting it in the bank and earning interest. Future money is also less valuable because inflation erodes its buying power. This is called the time value of money. But how exactly do you compare the value of money now with the value of money in the future? That is where net present value comes in.  ... "