48÷2(9+3) = ???

[monster]

Originally Posted by Cloud

logically, how can 48 divided by anything be 288? I still say 2

if you then multiply it by 12

[Clodfobble]

Originally Posted by Undertoad

no i did the parens first and then, from left to right, division and then multiplication

You don't do multiplication/division from left-to-right like it's prose. Multiplication comes first regardless of where it is. Assume that the parentheses are done first, so now we have:

48 ÷ 2 x 12

That is the same as

48 x (one-half) x 12

Your way puts the 12 as a denominator in the fraction, which it wouldn't be unless there were also parentheses around the (2 x 12).


The mnemonic they taught us in grade school was My Dear Aunt Sally: multiplication, division, addition, then subtraction.

[Undertoad]

Multiplication AND division are done first...

[monster]

Originally Posted by Undertoad

it is written that way.

brackets first 9+3 = 12

then division 48/2 = 24

then multiplication 24 * 12 = 288

(a) No, it isn't written that way
(b) you're relying on Wikipedia

[Undertoad]

Google and Wolfram Alpha agree with me.

[monster]

Originally Posted by Undertoad

Multiplication AND division are done first...

there is no left to right in math. when there are both multiplication and division, multiplication goes first. that's why 2(whatever) means 2 * whatever. There is no division equivalent because it isn't needed because multiplication happens first

[monster]

Originally Posted by Undertoad

Google and Wolfram Alpha agree with me.

they're wrong.

[Juniper]

Order of operations: PEMDAS

Parentheses, equations, multiplication, division, addition, subtraction.

However, multiplication/division and addition/subtraction are equal.

Therefore, the answer is 24 x 12 = 288

Slinking back into the shadows now.

[monster]

Originally Posted by Juniper

Order of operations: multiplication, division,

However, multiplication/division and addition/subtraction are equal.

you are contradicting yourself. If they were equal, one wouldn't be before the other on the order of operations. Generally, there is no difference, but this is the illustration of why there is an order of ops that puts mult before div.

[monster]

At what point do I point out my BSc (honours) in math? I don't care what wikipedia says that google fetches up and other shit..... The answer is 2.

[Undertoad]

Yes but you got that degree off the back of a cereal box and I claim victory.

[Juniper]

PEMDAS is easier to say than PEDMSA but I guess you could do PEDMAS or BEDMAS (for brackets) and it wouldn't really matter. That's the way I was taught, back in the ice age.

Maybe I ought to ask my kids. I'm really not smarter than a 5th grader.

Or in my case, 7th grader and 9th grader . . . OMG, the 9th grader asked me for math homework help and I Could Not Do It. Algebra. Polynomials. ::::

[monster]

Originally Posted by Undertoad

Yes but you got that degree off the back of a cereal box and I claim victory.

No, I didn't, and PEMDAS backs me up. Claim all the victory you like, you're still wrong.

Juniper, it does matter, that's why it's PEMDAS and nothing else. It just doesn't matter very often.

Math is not left to right -maybe that's why left-handers are good at it?

[skysidhe]

288, just because I plugged it into my calculator as written.

[Undertoad]

Maybe my BSCS and three decades of computer programming will count for something?