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Original poster

40+40x0+1 ?

539 replies

minimuffy · 09/11/2011 19:48

40 + 40 x 0 + 1 =

A- 1
B- 41
c- 0

I say its B-41 as you need to multiply then add. (from what i remember of standard grade maths the acroymym BOMDAS- brackets off, multiply, divide, add, subtract)

DH says its 1.

please tell he's wrong!

OP posts:
schnitzelvoncrumm · 10/11/2011 18:45

and changebags oh yes, you can say things equal infinity. Infinite arithmetic is a whole load of fun.

For example, mathematicians can prove (without any maths that's too high powered or complicated) that:

  1. there are infinitely many natural (counting) numbers
  2. there are infinitely many odd numbers
  3. there are infinitely many even numbers
  4. there are infinitely many primes
  5. there are infinitely many square numbers
  6. there are infinitely many real numbers (numbers with decimal points, not just the whole ones) 7)confusingly there are the same number of natural numbers, odd numbers, primes, even numbers, and square numbers. That is, the set of all numbers (odd and even) is the same size as the set of odd numbers. However, there are infinitely many real numbers, but it's a bigger infinity than the infinity that describes the size of the set of natural numbers. Cool, huh?
schnitzelvoncrumm · 10/11/2011 18:41

Mathematicians don't divide by zero. What they do do, is divide by ever smaller numbers and see what they get.

So they might see what the limit, as n tends to zero of 1/n is.

That's easy.

1/1 = 1
1/0.5=2
1/0.25=4
1/0.125=8
...

and so on. To prove that 1/n does indeed tend to infinity, as n tends to zero, and not just a very very big finite number they will show that for any number M (anything you like) there exists epsilon such that 1/epsilon is bigger than M.

Changebagsandgladrags · 10/11/2011 18:04

Even mathematicians aren't really supposed to divide by zero. To test for an infinite series you're supposed to take the reciprocal, so 0 divided by something equals 0. Then say as the reciprocal tends to zero, so the series tends to infinity.

But we can never say something equals infinity like we could about an actual number.

GrimmaTheNome · 10/11/2011 17:36

Infinity can be treated as a number in some contexts (e.g. infinite series) but computers have it about right when they choke and sick up NaN (Not a Number) if you're foolish enough not to test for a zero denominator.

nickelbabe · 10/11/2011 17:28

infinity is treated as a number - see Tianc's link.
undefined can never be treated as anything, because it's undefined

nickelbabe · 10/11/2011 17:27

Longtime - you were probably sent the thread to ponder the extra bits we've put in after the OP was answered Grin

Longtime · 10/11/2011 17:23

I've been sent to this thread (maths tutor) but I see I'm not needed as many have given the answer and the reason why. It's 41 as you multiply first.

40 + 40 x 0 + 1 = 40 + 0 + 1 =41

Tianc · 10/11/2011 16:24

Wikipedia: "In mathematics, "infinity" is often treated as if it were a number (i.e., it counts or measures things: "an infinite number of terms") but it is not the same sort of number as the real numbers."

It can be useful to be able to integrate from 0 to infinity, say.

Pakdooik · 10/11/2011 16:23

Stranded & Totem. Ah, I see what you're getting at. I assumed there was an external "right" answer.

In that case, it's nonsensical as there's no 60% answer. It's also nonsensical 'cos it's circular.

TotemPole · 10/11/2011 16:20

pak,

If the correct answer is 25% odds are 2/4, so the correct answer is 50%, i.e. 1/4 and so on.

TotemPole · 10/11/2011 16:18

Infinity isn't a number, it's a concept.

StrandedBear · 10/11/2011 16:18

This reply has been deleted

Message withdrawn at poster's request.

hocuspontas · 10/11/2011 16:16

Thanks!

Pakdooik · 10/11/2011 16:14

Stranded I'll bite

If the correct answer is 50% odds are 1/4
If the correct answer is 60% odds are 1/4
If the correct answer is 25% odds are 2/4

nickelbabe · 10/11/2011 16:11

it is infinity.

of course it's infinity.

it's not "undefined" because "undefined" is not a number.

TotemPole · 10/11/2011 16:09

hocuspontas, in to out. Within the brackets you follow the same order, BODMAS.

StrandedBear · 10/11/2011 16:09

This reply has been deleted

Message withdrawn at poster's request.

rushofbangerstothefire · 10/11/2011 16:07

Oooh, that IS mind-blowing Stranded, because if you pick the right answer you immediately change the outcome. It's cats in boxes all over again!

hocuspontas · 10/11/2011 16:06

At grammar school in the 60s we learnt BMDAS (Bless My Dear Aunt Sally). Something I've never ever forgotten BUT can someone tell me the order of resolving brackets? Is it left to right or do you resolve division within brackets followed by multiplication in brackets etc. Or doesn't it matter? Confused

noblegiraffe · 10/11/2011 16:03

Infinity isn't a number! The answer to a calculation can't be infinity. A number divided by zero is undefined.

StrandedBear · 10/11/2011 16:01

This reply has been deleted

Message withdrawn at poster's request.

StrandedBear · 10/11/2011 15:55

This reply has been deleted

Message withdrawn at poster's request.

amicissima · 10/11/2011 15:48

This reply has been deleted

Message withdrawn at poster's request.

GrimmaTheNome · 10/11/2011 15:44

Stranded - nope. Its infinity. (hows your head? Grin)

LeBOF · 10/11/2011 15:39

Ahaaaaahaaha- excellent, GettingALifeNow.

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