Why carefull? I am dated enough because am retired ( and I had calculus in high school, lol).

As for the simple technique, something is better than nothing, after all it looks like some folks here have little idea as to value of shares they own or how do they compare to others.

And more involved methods I even rarely try myself ( hence dated ) let alone for some one else. The simple one serves me well enough most of the time.

If any one wants to go to the effort of finding current or future value using better method and posting it, I would be very appreciative. Thanks.