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Question #93341 posted on 09/27/2020 2:38 p.m.
Q:

Dear 100 Hour Board,

I have a calculator called a Texas Instruments BA-II Plus specifically targeted toward business analysts and one of the "features" is to either turn on or turn off the rounding of intermediate values in the multistep calculations it can do.

Someone who knows the type of math business folks do, why would you specifically want to round intermediate values in calculations?

-Bill

A:

Dear Bill,

For multi-step calculations, storing all the long intermediate values can take up a lot of memory. As some numbers literally go on forever (i.e. all irrational numbers), it's impossible to store all of even a single number in memory. So everything, from the simplest pocket calculator to super-computers have to round to some degree. These small errors can add up, which is actually why it's common for mathematicians or programmers to take the logs of really small numbers used in calculations, as that helps prevent these errors from blowing up.

All of this is to say that rounding of some form is most likely taking place; this feature is probably just adjusting how much rounding it's doing. As far as why it's offered to business people, my guess is that whatever watered-down math they're doing, they don't need to be super accurate (keep in mind that as a mathematician, I have a very rigorous concept of what it means to be accurate, so I'm not implying that business people don't still need to be accurate). 

~Anathema