(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
You’re reciting the “rule” that people learned in elementary school. But, that’s not actually “the” rule. In fact, there isn’t a single rule. Sometimes people round up (common if, for example, you’re computing sales taxes) or round down (common if, for example, you’re paying out interest on a savings account).
Then, there’s “round to the nearest…. ,” but that leave some ambiguity — what do you do if you’re *exactly* half-way between? This is the problem our elementary school teachers were trying to solve by saying “if it’s 0.5, you round that up to 1 and not down to 0.” But, that’s just a convention that was useful in elementary school to ensure that every student got the same answer. But, in real life, sometimes, people will round 0.5 down to 0.
The good thing is that this actually doesn’t come up all that often — when you’re rounding, it’s usually because you’re doing a measurement of some sort. And, it’s really rare for measurements to be *exactly* half way. You almost never have “7.5 miles.” It’s always something like 7.4995 or 7.5001 miles.
In the few cases out there where it’s possible to be half way (“these nails are half a cent each”), always a good idea to ask how rounding happens.
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