(Disclaimer: I have ADHD and am completely useless when it comes to math. So please forgive me for being super-stupid on the subject.)
To my understanding, Mathematics are seen as completely logical. Which I don’t have a problem with except for when it comes to one certain thing in math that I just can’t make sense of as being considered logical:
Rounding of decimals.
To my understanding, the rule is that when you have a decimal that is 5 or higher, you round up. If 4 or lower you round down.
Two things that I don’t understand about this:
1. When you round up, you magically pull value out of the air that wasn’t there to begin with, and do the opposite when rounding down. How is this considered logical?
2. The rule isn’t applied universally. I’ve seen cases when, for example, making store purchases, no matter how low the decimal, it is rounded up and not down.
I appreciate any help you guys can give. Thank you in advance for the assistance! <3
In: 6
Mathematics are built on logic. But so is physics, therefore chemistry, therefore biology, therefore psychology, and we’re not completely logical, are we?
Rounding isn’t a matter of math, it’s a matter of presentation. We write either π or 3.14, we don’t write every known digit of pi. Not because π=3.14, but because we have no use for so much precision, and because they wouldn’t fit meaningfully on a page.
As a method of presenting numbers, the intent of the presentation matters. Usually, you round to the “nearest” number because it balances an accurate representation of reality against the limitations of human perception.
If you’re buying a new airplane, you’ll round the price to the nearest couple digits of a million dollars on marketing materials, but you’ll round to the nearest cent on the bill. You’ll round down if the question is “how many whole apples have you got” because 3/4 of an apple isn’t a whole apple. You’ll round up to the nearest cent because the halfpenny is discontinued. All of this is done according to the interests of whomever presents that number. Of course a store will round up if they can get away with it.
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