this post was submitted on 03 Mar 2024
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[–] [email protected] 59 points 8 months ago (6 children)

0.5 / 0.5 = 1, so reducing the top term by half (from 0.5 to 0.25) reduces the result by the same (from 1 to 0.5), makes perfect sense to me. Or, ya know, just remember that dividing by 0.5 is the same as multiplying by 2.

[–] [email protected] 13 points 8 months ago (1 children)

Or even simpler the half of 0.5 fits into 0.25. And we all know a half is 0.5

[–] [email protected] 6 points 8 months ago

I was trying to think how to put that into words with an example like, "how many halves fit in 10? It's 20. So how many halves fit in a quarter? Only half of a half will fit, so 0.5" but I kept screwing up the wording in my head for halves and quarters until I read your reply, so thank you for helping with that clarification. I knew the math was right but couldn't put it into words the way I wanted.

[–] [email protected] 8 points 8 months ago (1 children)

0.5 / 0.5 = 1

Fuck you, that's even worse!

[–] [email protected] 14 points 8 months ago (2 children)

x / x = 1

really shouldn't make anyone upset

[–] [email protected] 6 points 8 months ago

It is the same as 1*x = x

I give you x, once. How many do you have?

[–] [email protected] 3 points 8 months ago* (last edited 8 months ago) (1 children)
[–] [email protected] 8 points 8 months ago

Then X can start tending to hell

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[–] [email protected] 43 points 8 months ago (1 children)

If you move it around it makes more sense.

.25 = 0.5*0.5

If you take half of something only half of the time you take a quarter of something.

[–] [email protected] 7 points 8 months ago (1 children)

I see it more clear with this: 0.25 * 2 = 0.5

Dividing by 0.5 is like multiplying by 2.

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[–] [email protected] 29 points 8 months ago

Not weird or disturbing at all

[–] [email protected] 27 points 8 months ago
[–] [email protected] 16 points 8 months ago

Stupid Lemmy making me do maffs on a sunday >:(

[–] [email protected] 16 points 8 months ago

Dividing by a division of 2... Of course it's going to cancel out. Like subtracting a negative.

Surely you don't not understand double negatives? Just think of it like that.

[–] [email protected] 15 points 8 months ago (10 children)

Maybe someone better at math can answer this, but is 0.25/0.5 functionally the same as 0.5/1, or simply 0.5?

[–] [email protected] 17 points 8 months ago (1 children)

You can call it whatever you want, as long as it equals 1/2 it's the same number.

So yes, multiplying by 2/2 to make it more intuitively obvious is perfectly valid and a good way to think about it. Most arithmetic tricks are ultimately multiplying by 1 or adding 0 just to make the problem easier to handle.

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[–] [email protected] 4 points 8 months ago* (last edited 8 months ago)

I think it's easier to picture it in terms of fractions. When you divide by a fraction, you reciprocate the divisor. That is, you flip its numerator and denominator, then multiply them. In this case, we're taking 1/4 and dividing it by 1/2. You take the reciprocal of 1/2, which is 2/1. Then multiply the numerators and denominators. You end up with (1/4)*(2/1)=2/4=1/2=0.5

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[–] [email protected] 14 points 8 months ago

Dividing by 0.5 is the same as multiplying by 2. Simple

[–] [email protected] 11 points 8 months ago

0.25 / 0.5 = 0.25 * 2 = 0.5

[–] [email protected] 9 points 8 months ago

Everything I see memes like this I think:

“Do other people just not get basic math?”

[–] [email protected] 8 points 8 months ago

This is 25/50

[–] [email protected] 8 points 8 months ago* (last edited 8 months ago)
  • 250 marbles / 500 kids = 0.5 marble per kid
  • 25 marbles / 50 kids = 0.5 marble per kid
  • 2.5 marbles / 5 kids = 0.5 marble per kid
  • 0.25 marbles / 0.5 kids = 0.5 marble per kid, but there's only one half a kid with a quarter of a marble in this example.
[–] [email protected] 8 points 8 months ago* (last edited 8 months ago)

0.5 = 1/2, 0.25 = 1/4

0.25 / 0.5 = (1/4) / (1/2) = 1/4 * 2/1 = 2/4 = 1/2 = 0.5

[–] [email protected] 6 points 8 months ago (1 children)

In case people would like it demonstrated,

0.25/0.5

= 1/4 ÷ 1/2

= 2/4 ÷ 2/2

= 1/2 ÷ 1

A÷1 = A, therefore 0.25/0.5 = 0.5

Alternatively, (a/b)/(c/d) = (a×d)/(b×c)

1/4 ÷ 1/2 = 1×2 ÷ 4×1 = 2/4 = 1/2

[–] [email protected] 5 points 8 months ago

And before any pedants crawl out of the woodwork, there are a load of implied brackets, at the spaces.

[–] [email protected] 6 points 8 months ago (6 children)

I understand this mathematically, but can somebody explain it logically?

[–] [email protected] 12 points 8 months ago

0.25 is half of 0.5

[–] [email protected] 10 points 8 months ago

Multiplying by 0.5 halves. Dividing would double the number. 0.25 doubled is 0.5.

Sleep well!

[–] [email protected] 6 points 8 months ago* (last edited 8 months ago)

y/x = x with y = x*x because 0.25 is 0.5 squared.

from the "wow factor" it's the same as writing: 9/3 = 3 - not very wow at all

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[–] [email protected] 4 points 8 months ago (1 children)

Every time I see something like this, the comments remind me that common core mathematics is a thing and it makes me sad.

[–] [email protected] 10 points 8 months ago (1 children)

Seriously, why is basic arithmetic worthy of so much discussion?

Just... do the math. It's not complicated math.

[–] [email protected] 7 points 8 months ago

I sometimes feel bad about myself cause I didn't get very far into calculus, but then I remember that the average adult has no idea how fractions work.

[–] [email protected] 4 points 8 months ago

Nice little trick in the weird syntax we call math.

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