40+40x0+1 ?

[minimuffy]

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!

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

Thanks!

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

pak,

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

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.

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.

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

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

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

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.

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.

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.

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?

Yes but... you can say there are 'infinitely many natural numbers' but I'm not sure you can technically say 'the number of natural numbers equals infinity' because infinity is Not a Number (as your point 7 helps demonstrate)

Schnitzel, my brother explained that to me; it really is cool! I love the idea that there are infinitely many infinities ........

Philosophers say that you can't have an infinite regression, but I don't really see why you can't. I think it's the same sort of thing, leads you to places where you need greater expertise than the layman usually has.

B = 41

saying something is infinite is different to saying it equals infinity.

So, like you say, there are infinitley many primes. But you can't say the amount of prime numbers equals infinity.

You can only ever say there are an infinite amount of things or that a certain thing tends to infinity, not that it is infinity.

Catch up, dear !

I am back from parents' evening. And had .
Apparently DS1 (8) is on the financial team for their class enterprise and has informed the packaging team (for their baked goods) that they cannot have tissue paper to wrap their biscuits in as 'it is too expensive and our profit would only [sic!] be 85%' - moneygrabbing little sod

So, we've had infinity, Pi(e), Fibonacci numbers (wtf?) - this must be the Cleverest thread on MN. Ever.

Must be time for maths jokes. Here's my old favourite:

There are 10 types of people in the world.
Those who understand binary and those who don't.

- See, I got that, I is clever afterall

Actually, when you're doing arithmetic with infinite cardinal numbers, you can (and must) use equals signs. I agree that saying something "equals infinity" is vague, but you do have equations with infinite cardinals on both sides.

I didn't think I'd ever need an aleph on mumsnet (that's when you don't just use greek letters for your algebra but borrow a hebrew one!) but here's the link to the wiki page on cardinal numbers for those interested: en.wikipedia.org/wiki/Cardinal_number

Gosh, schnitzel, you're not involved in number theory are you?

For iPad users, just download Wolfram Alpha, it'll do any calculation you could possibly want, and it's free, and you can have it on your phone and on your computer. I have it on all my devices, and never use anything else. There are loads of free calculator progs for iPads, none of which would ignore the x0 or come up with 1 as the answer to the first question.