# 48÷2(9+3) = ? | Questions that make you think... | Forum

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48÷2(9+3) = ?
June 12, 2012
3:30 pm
at1with0
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Many people will get 2.

Subtraction is the same as adding the additive inverse (the opposite) and division is the same thing as multiplying by the multiplicative inverse (the reciprocal).

Therefore, 48/2(9+3) is 48*.5*(9+3) which is 24*12 = 288. (.5 is the reciprocal of 2)

When using the PEMDAS convention, M and D are done simultaneously left to right because multiplication is commutative and since D is really M by the reciprocal. When using the PEMDAS convention, A and S are done simultaneously left to right because addition is commutative and since S is really A of the opposite.

Every expression can be re-written to not use division and to not use subtraction. You'll have multiplication by the reciprocal and adding the opposite. When doing that, PEMDAS simplifies to PEMA.

"it is easy to grow crazy"

June 13, 2012
9:18 am
Nesaie
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You math geek! 😛

So maybe, as above so below? Or maybe we can exclude below or above? I'm sure you're one of the few people who could get these questions.

Such a society would be dominated by an elite, unrestrained by traditional values. Soon it will be possible to assert almost continuous surveillance over every citizen... - Zbigniew Brezhinsky

June 15, 2012
3:28 am
gumrosin
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288

June 15, 2012
10:12 pm
at1with0
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"it is easy to grow crazy"

June 28, 2012
4:32 am
SmokinJoe
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"at1with0" wrote: Many people will get 2.

Therefore, 48/2(9+3) is 48*.5*(9+3) which is 24*12 = 288. (.5 is the reciprocal of 2)

Every expression can be re-written to not use division and to not use subtraction

That is amazing. In school, you are taught to first work the right side of the problem (9+3). Then move left..so it looks like this:
(9+3) is 12...
2(12)
24
48/24
2

But he actually starts with 2 being the critical link between both equations.

48/2 (or 48*.5)
24
then he goes to the right side..

(9+3)
12

bringing it home...
24 x 12 = 288.

It is the exact same equation with 2 outcomes depending on one's interpretation of it. That is a great metaphor in life. Also, if you aren't open to other interpretations, you just won't see it.

AWESOME video, at1... :thumbup:

Dawkins thinks belief in God is an excuse to evade thinking in the scientific world. Sadly, he is ignorant to the list of christian scientists who have contributed & founded many of the sciences he himself believes in. How ironic.

June 28, 2012
4:47 am
at1with0
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The result is 100% dependent on what convention you use.

"it is easy to grow crazy"

June 28, 2012
5:09 am
SmokinJoe
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"at1with0" wrote: The result is 100% dependent on what convention you use.

LOL..yup!

Dawkins thinks belief in God is an excuse to evade thinking in the scientific world. Sadly, he is ignorant to the list of christian scientists who have contributed & founded many of the sciences he himself believes in. How ironic.

June 28, 2012
6:07 pm
at1with0
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Apparently, this discussion (whether it "is" 2 or 288 or something else) rages on in the interwebs. A ring theorist studies generalizations of the integers (which form the prototypical example of a ring) all day long but that in itself doesn't make him an authority on integers because arithmetic is pretty far removed from what they do in day-to-day work. They think about pretty strange, abstract stuff far removed from actual numbers.

"it is easy to grow crazy"

July 5, 2012
9:02 am
bionic
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I get 24..

Willie Wonka quotes..
What is this Wonka, some kind of funhouse?
Why? Are you having fun?
A little nonsense now and then is relished by the wisest men.
We are the music makers, we are the dreamers of dreams

July 5, 2012
2:49 pm
at1with0
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"it is easy to grow crazy"

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