this post was submitted on 14 May 2024
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Memes

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[–] [email protected] 117 points 7 months ago

Intuitively speaking, how many times does half of a thing fit into a quarter of a thing? The answer is, exactly one half time.

[–] [email protected] 98 points 7 months ago (1 children)

How many halves fit into a quarter? Half of them

[–] [email protected] 19 points 7 months ago

That's exactly how I think of it, so strange someone downvoted you

[–] [email protected] 66 points 7 months ago* (last edited 7 months ago)

✅ Math is hard

❌ This math is hard

[–] [email protected] 34 points 7 months ago

0.25 / 0.5 = 0.5
0.25 = 0.5 × 0.5
1/4 = 1/2 × 1/2

[–] [email protected] 33 points 7 months ago (1 children)

p/q=q

So q=√p

Works with a lot of numbers ☝🏻🤓

[–] [email protected] 11 points 7 months ago (1 children)

Ehhh |q| = √p but close enough

[–] [email protected] 3 points 7 months ago

If q=√p then -q=√p also.

[–] [email protected] 30 points 7 months ago

This is why "divide by half" and "divide in half" are two different things

[–] [email protected] 24 points 7 months ago (2 children)

It won’t keep you up if you just think of Divide as just multiplying by the fraction

[–] [email protected] 5 points 7 months ago (1 children)

Yeah I was gonna comment that 0.25*(1/0.5) = 0.5 doesn't look nearly as weird

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

I didn’t specify fully, but I was just thinking 1/4 * 2/1

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[–] [email protected] 4 points 7 months ago (1 children)

The math looks perfectly fine. But when people phrase "half of a quarter" I think they have (1/2)*(1/4) in mind, instead of 0.25/0.5

[–] [email protected] 4 points 7 months ago (1 children)

But this isn't "half of a quarter" this is "the reciprocal of a half, of a quarter"

Half of a quarter is 0.25/2 or 0.25*1/2

[–] [email protected] 5 points 7 months ago (2 children)

I know, but to me this meme doesn't make sense to me unless I assume the person reading the math Expression is interpreting its real world application.

25 / 5 = 5 and nobodies head exploded. That's just evaluating a math Expression. .25 / .5 = .5 is the same. It's not a "my brain can't comprehend how to evaluate expressions" as the meme suggests.

However, if someone who doesnt do much algebra thought to themselves "I need half of a quarter", then I could understand why their brain might "hurt" as the meme suggests, for a similar reason why adding 20 degree Celsius water to 20 degree Celsius water doesn't make 40 degree Celsius wate

I'm probably reading into it too much, but the meme just doesn't feel like a "mind fuck that keeps me up at night". I'm looking for reasons to try and explain it, but it's just a math expression at the end of the day

[–] [email protected] 2 points 7 months ago

I think you nailed the confusion in this meme.

To simplify: it's confusing that ½ = 0.5, but 1/2 ≠ 1/0.5

[–] [email protected] 2 points 7 months ago

I think the meme is an exaggeration of the situation for comedic effect. It just looks silly at first glance, I don't believe the OP is kept up at night by this, and is rather making a remark about how it doesn't instantly feel intuitive as a result (to use the 20 Celsius water example, its the same kind of momentary "wtf?" as 40 Celsius water not being twice as hot as 20 Celsius water. After a moment you remember "oh derp yeah we're missing 273.15 kelvin in this picture lol")

[–] [email protected] 22 points 7 months ago (1 children)

If you give half a person a quarter of a thing, how much would you be giving a full person? That's right baby, half a thing. Don't sweat it.

[–] [email protected] 15 points 7 months ago

x / sqrt(x) = sqrt(x)

Damn who would've thought?

[–] [email protected] 14 points 7 months ago* (last edited 7 months ago)

Divide by 1/2 or multiply with 2/1. It's an equivalent transformation.

[–] [email protected] 12 points 7 months ago (1 children)

I just think of division as how many times the right expression fits inside the left expression. 0.5 fits into 0.25 only 0.5 aka 1/2 times, because only half of it fits.

[–] [email protected] 10 points 7 months ago

Precisely this. The people not getting the OP are why Common Core was developed.

[–] [email protected] 11 points 7 months ago

The numbers between zero and one are where all of the fun is!

[–] [email protected] 11 points 7 months ago
[–] [email protected] 10 points 7 months ago

1×2=2

Wow. Much brain. Maths wow.

[–] [email protected] 9 points 7 months ago (1 children)

A quarter is one half of one half. Makes perfect sense.

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[–] [email protected] 8 points 7 months ago* (last edited 7 months ago) (3 children)
[–] [email protected] 5 points 7 months ago

I think, it is the real world logic that makes it hard to grasp. If you divide something with something small it becomes bigger. Mathematically it's easy and makes sense, but it it's somehow not intuitive. Especially for young me :)

[–] [email protected] 3 points 7 months ago

That's the same as 2/2=1 3/3=1 268/268=1 ...

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

This just comes down to the fact that "dividing by a fraction is the same as multiplying by the inverse of the fraction" is an easy rule to follow but not particularly intuitive. In natural language, when most people hear "divide by half" they're actually picturing "divide by two" in their head.

[–] [email protected] 5 points 7 months ago (3 children)

This don't avoid to sleep not even for 1/2 second. But pick any number. If that number is even, divide it by 2. If it's odd, multiply it by 3 and add 1. Now repeat the process with your new number. If you keep going, you'll eventually end up at 1.

[–] [email protected] 13 points 7 months ago (1 children)
[–] [email protected] 9 points 7 months ago* (last edited 7 months ago)

Yes, but everyone tried since a century to find a number with which it don't work, good to avoid sleep.

[–] [email protected] 2 points 7 months ago

Any positive number?

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[–] [email protected] 5 points 7 months ago* (last edited 7 months ago) (1 children)

It’s going to be okay:

Edited to add this: Singapore math insists however, that we eliminate the use of visuals in describing arithmetic within the rationals. They encourage that users of common core rely upon the number line, and solely the number line for thorough and most mathematically sound representations of arithmetic, even when involving the division of fractions.

For those not up to speed to with common core, remember how the teacher used to draw a diagram of a bunny hopping from one integer to the next integer to represent adding given integers, such as 4+3, or -2+1? Imagine that representation being used with problems like 1/7 divided by 5/49, and no decimal approximation is allowed. It’s fascinating and truly something to appreciate from the standpoint of someone who truly loves mathematics. I think it makes for great discussions amongst math graduates like myself, and other math enthusiasts. What does that mean for those who are not so enthused? Sometimes it means the teacher receives death threats from angry students. You can’t make everyone happy.

[–] [email protected] 3 points 7 months ago (1 children)

I’m not sure I completely agree with the number-line-only approach, but I’m definitely sympathetic to it. It reinforces the idea that fractions are numbers like any other numbers, and not pieces of pizza.

[–] [email protected] 3 points 7 months ago

I get that. I like the number line approach, and respect it, but I have also observed seasoned math coaches fumble the visual explanation of a division by fractions problem where the numerators and denominations were relatively prime. As soon as the guy had drawn the first fraction and began to say, “we’d multiply by the recipro-…”, I could tell it was going to be long problem. He just stood there, and then asked, “well, how would I go about explaining the ‘keep change flip’, if you will?” He ended the problem by saying he might just explain that the distance drawn for the first fraction needs to be repeated on the other side of the fraction to show the multiplication by the denominator of the second fraction, and then that distance could be broken into parts to demonstrate the division by the previous numerator of the second fraction.

Basically he ended the problem by saying, “let’s just reflect it! Then we can break it up.” There wasn’t really a sound justification for the reflection piece of the process, other than saying, “we need to multiply by the reciprocal of the second fraction, so we’ll just have to multiply by its denominator it had, prior to flipping it.”

That was the quietest meeting I have ever seen amongst that group of adults.

[–] [email protected] 3 points 7 months ago (1 children)

Multiplication of x times 6:

x * 6 = 1/2 x * 10 + x

This can sometimes be a shortcut for numbers that are easier to divide by 2 than to multiply by 6.

Take half as tens and add the number.

6 * 6 = 30 + 6 = 36

8 * 6 = 40 + 8 = 48

150 * 6 = 750 + 150 = 900

320 = 1600 + 320 = 1920

Etc.

Sleep well.

[–] [email protected] 2 points 7 months ago* (last edited 7 months ago) (2 children)

So an extension of the x * 5 = x/2 * 10 shortcut

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[–] [email protected] 3 points 7 months ago* (last edited 7 months ago)

2^-2 * (2^-1)^-1 = 2^-2 * 2^(-1 * -1) = 2^(-2 + -1 * -1) = 2^(-2 + 1) = 2^-1 = 1/2 = 0.5

[–] bitfucker 2 points 7 months ago

Man, I thought this is an ADHD meme when trying to sleep and your brain starts to do random shit.

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