flibble
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| posted on 20/8/12 at 01:40 PM |
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Poll - What is 3+4x5?
Just in the middle of a minor disagreement and wondering if I'm in the wrong (I won't say which I think it is) 
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Irony
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| posted on 20/8/12 at 01:50 PM |
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23. Multiplication comes before addition. The expression would be written 5(3+4) = 35
Wow - my A-level in maths has just proved useful!
[Edited on 20/8/12 by Irony]
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blakep82
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| posted on 20/8/12 at 01:52 PM |
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if its as is there, then if you put it in a calculator, its 35.
if any parts are in brackets, ie 3+(4x5) then its 23, as its 3+ the answer of 4x5.
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Rod Ends
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| posted on 20/8/12 at 01:54 PM |
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BODMAS - O level Maths - (which doesn't exist anymore) - it's called A level Maths! 
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loggyboy
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| posted on 20/8/12 at 01:57 PM |
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Surely if you multiply first the answer is 23:
3+(4*5) :-
3+20=23
Mistral Motorsport
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blakep82
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| posted on 20/8/12 at 02:01 PM |
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http://www.wolframalpha.com/input/?i=3%2B4x5
hmm, can't argue with that, but i don't really understand it lol 
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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Dale
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| posted on 20/8/12 at 02:02 PM |
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Loggyboy is correct as I remember. enter it into google and it also shows 23
Brakets are assumed around the mulitiplication.
Dale
Thanks
Dale
my 14 and11 year old boys 22
and 19 now want to drive but have to be 25 before insurance will allow. Finally on the road
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MikeRJ
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| posted on 20/8/12 at 02:06 PM |
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quote:
Originally posted by Irony
Multiplication comes before addition. The expression would be written 5(3+4) = 35
Wow - my A-level in maths has just proved useful!
Except that you've just forced the addition to be completed before the multiplication by adding parentheses, and therefore get the wrong
answer!
If you are using the standard rules of operator precedence then:
3+4x5 = 3+(4x5) = 23
quote:
Originally posted by blakep82
if its as is there, then if you put it in a calculator, its 35.
Only if your calculator is broken!
[Edited on 20/8/12 by MikeRJ]
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bartonp
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| posted on 20/8/12 at 02:07 PM |
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Let me correct the sum for you:
4 5 x 3 + =23
(RPN)
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stevegough
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| posted on 20/8/12 at 02:10 PM |
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Aye. BODMAS. Remember it well.
Brackets,
Order,
Division,
Multiplication,
Addition,
Subtraction.
As there are no brackets, you follow the order.
Hence 3+4 = 7, then 7x5 = 35.
God, is there nothing this forum can't answer? 
Luego Locost C20XE.
Build start: October 6th 2008.
IVA passed Jan 28th 2011.
First drive Feb 10th 2011.
First show: Stoneleigh 1st/2nd May 2011.
'Used up' first engine may 3rd 2011!
Back on the road with 2nd engine may 24th
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Sold to Mike in Methyr Tydvil 19/03/14
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flibble
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| posted on 20/8/12 at 02:10 PM |
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That's quite a split vote so far!
I was taught BIDMAS, yet was having a discussion with my friends daughters teacher who said the above sum gives 35, I said 23 and wondered if things
had changed or if I'm having a dopey moment (which is quite possible)!
As a side note to education, I've always kept my books etc from the start of school, and if I look back through them it seems what I learnt aged
6, they're teaching similar at aged 8+.
By age 5 I could count and write (as could all my friends) to a fair degree but none of my friends children could until much later and still seemed to
be praised as high achievers at school.
Edit, we were told to swap the Order for Indeces to clear things up?
[Edited on 20-8-12 by flibble]
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Confused but excited.
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| posted on 20/8/12 at 02:15 PM |
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quote:
Originally posted by stevegough
Aye. BODMAS. Remember it well.
Brackets,
Order,
Division,
Multiplication,
Addition,
Subtraction.
As there are no brackets, you follow the order.
Hence 3+4 = 7, then 7x5 = 35.
God, is there nothing this forum can't answer?
If you actually follow your own reasoning, ie; BODMAS, and follow the order, then multiplication still comes before addition and the correct answer is
still 23!
Tell them about the bent treacle edges!
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blakep82
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| posted on 20/8/12 at 02:15 PM |
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^ so since the 3 is before the 4, is it then 5x3 (=15) +4 which is 19 lol
quote:
Originally posted by MikeRJ
quote:
Originally posted by blakep82
if its as is there, then if you put it in a calculator, its 35.
Only if your calculator is broken!
[Edited on 20/8/12 by MikeRJ]
well, depends how the calculator works its seems. windows calculator comes up with 35 when you type 3+4x5 and then =
my phone comes up with 19 when you type in 3+4x5 and then =
the calulator on windows works out the sum when ever you type in an action (+, -, x etc) my phone doesn't, it only works out an answer when you
press =
i was terrible at maths in school, but i don't remember any mention of multiplications being done before anything else, only ever things in
brackets should be done before anything before or after. weird how a simple sum can get different wrong answers
[Edited on 20/8/12 by blakep82]
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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whitestu
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| posted on 20/8/12 at 02:19 PM |
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quote:
If you actually follow your own reasoning, ie; BODMAS, and follow the order, then multiplication still comes before addition and the correct answer is
still 23!
Just what I was thinking! The answer is 23. I've checked this with my 10yr old so I'm sure it is correct, as he has had this stuff drilled
into him for the last year in preparation for his 11+!
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loggyboy
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| posted on 20/8/12 at 02:20 PM |
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quote:
Originally posted by stevegough
Aye. BODMAS. Remember it well.
Brackets,
Order,
Division,
Multiplication,
Addition,
Subtraction.
As there are no brackets, you follow the order.
Hence 3+4 = 7, then 7x5 = 35.
God, is there nothing this forum can't answer?
LOL obviously not that well!
The O stands for powers Of (not order!)
Those refering to calculators, i seem to recal their being types that worked out using bodmas, and cheaper ones that didnt. So its all down to user
inputing it correctly.
Either way the correct answer is 23
[Edited on 20-8-12 by loggyboy]
Mistral Motorsport
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02GF74
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| posted on 20/8/12 at 02:22 PM |
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there is only one correct answer.
getting different anwers using a phone, calculator, calc.exe, slide rule abacus etc is not the instrument's fault but indicates a lack of
understanding by the person using it: garbage in = garbage out.
mutliplication before addition. you cannot argue with maths.
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flibble
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| posted on 20/8/12 at 02:23 PM |
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quote:
The O stands for powers Of (not order!)
Hence why we were taught to swap the O(rder) for I(ndices), giving BIDMAS
[Edited on 20-8-12 by flibble]
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HowardB
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| posted on 20/8/12 at 02:25 PM |
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the O in order is not the order in which the calculation is written, but refers to raising a number to an order,.. ie squared or cubed.
BODMAS is the answer, and a proper calculator will always do the sum in that sequence.
the answer is 23
3+4x5=23=3+(4x5)
3+4x4=3+4squared=3+(4x4)=19
hope that helps
Howard
Fisher Fury was 2000 Zetec - now a 1600 (it Lives again and goes zoom)
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mcerd1
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| posted on 20/8/12 at 02:27 PM |
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another vote for BODMAS = 23
that's second year maths for me (the year before standard grades so ~1994  ) - what's an O level ?
quote:
Originally posted by blakep82
if its as is there, then if you put it in a calculator, its 35.
you need a better calculator then
a bog standard calculator expects you to know your BODMAS and adjust your inputs to suit
a better scientific or graphic calculator (or even MS Excel) will give you 23 even without brackets (the type where you type in the whole expression
then hit = )
my old casio's all do it correctly (fx-85, 83 etc...) at least the better do it right, there are a few hundred structures around the country
that rely on it.......
[Edited on 20/8/2012 by mcerd1]
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maccmike
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| posted on 20/8/12 at 02:28 PM |
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ill go with 23
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02GF74
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| posted on 20/8/12 at 02:37 PM |
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quote:
Originally posted by HowardB
3+4x4=3+4squared=3+(4x4)=19
hope that helps
eh? - how did 3+4x5 become 3x4x4?
your calculator need anew battery.
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HowardB
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| posted on 20/8/12 at 02:41 PM |
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quote:
Originally posted by 02GF74
quote:
Originally posted by HowardB
3+4x4=3+4squared=3+(4x4)=19
hope that helps
eh? - how did 3+4x5 become 3x4x4?
your calculator need anew battery.
It was an example of how raising a number to a power was the same as multiplication, but different to addition.
Either way the cry of BODMAS is one that needs upheld.
Howard
Fisher Fury was 2000 Zetec - now a 1600 (it Lives again and goes zoom)
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nick205
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| posted on 20/8/12 at 03:30 PM |
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On the calculator side, I notice my phone gives 35 in basic mode and 23 in scientific mode. Windows calculator works the same way too.
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britishtrident
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| posted on 20/8/12 at 03:39 PM |
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quote:
Originally posted by nick205
On the calculator side, I notice my phone gives 35 in basic mode and 23 in scientific mode. Windows calculator works the same way too.
Thats because in basic mode it is carrying out the operations in the order they are enter which is the only way it can do it.
In scientific mode it treats it was an equation, the operations are carried out after the equation is entered following maths rules it gives
multiplication precedence over addition.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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myke pocock
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| posted on 20/8/12 at 04:49 PM |
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35, the rest of you know NOOOTHING!!!
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