JT! Posted February 8, 2013 Report Share Posted February 8, 2013 Yeah, but you are adding the 10 to the second 2 (-2) rather than the first 2 (2) The operator ( * / + - ) belongs to the number directly after it, unless there are brackets after the operator. So the -2 doesn't get involved until the very end. Edit: This is very hard to explain over the internet and I am now getting confused... Well first of all you're saying -2 with no space. The question I stated has no negative numbers in it. You end up with 2 - 2 + 10. I don't really get why (when we're doing this strictly by bodmas rules) you'd do anything other than the 2+10 first. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted February 8, 2013 Report Share Posted February 8, 2013 Using brackets would solve all this 2 Quote Link to comment Share on other sites More sharing options...
Luke Rainbird Posted February 8, 2013 Report Share Posted February 8, 2013 Negative numbers are just positive numbers with an inverse operator. Like Andrew said before, each term has a sign (positive/negative) associated with it and you just add those up. The ambiguity tends comes in when multiplication/division gets involved hence brackets are handy, but addition/subtraction is so black and white.Perhaps moving to America was a wise move, JT Quote Link to comment Share on other sites More sharing options...
JT! Posted February 8, 2013 Report Share Posted February 8, 2013 So does (+2) - (+2) + (+10) = ? Make any difference to what we're talking about? You're still adding the 2 and the 10 together to get 12 according to bodmas regardless. Quote Link to comment Share on other sites More sharing options...
showurcolours Posted February 8, 2013 Report Share Posted February 8, 2013 So does (+2) - (+2) + (+10) = ? Make any difference to what we're talking about? You're still adding the 2 and the 10 together to get 12 according to bodmas regardless. No because it would look like (2-2) + 10. There is no possible way bidmas would give you 12 from that equation, no matter how you write it. Quote Link to comment Share on other sites More sharing options...
Revolver Posted February 8, 2013 Report Share Posted February 8, 2013 For example 4 x 2 ÷ 4 - 2 + 10 = ? This actually equals 10. Not -10. 4x2/4-2+10=4x0.5-2+10= 2-2+10= 2-12= -10 The bold shows the order that I calculated it according to bodmas. The thing I don't get is how you can say 'this actually equals 10' when bodmas is a rule that you can't ignore, so it actually equals -10. Quote Link to comment Share on other sites More sharing options...
Luke Rainbird Posted February 8, 2013 Report Share Posted February 8, 2013 So does (+2) - (+2) + (+10) = ? Make any difference to what we're talking about? You're still adding the 2 and the 10 together to get 12 according to bodmas regardless.You're on the right sort of lines, but you've actually got:(+2) + (-2) + (+10) You're not adding the 2 and 10, as that 2 is actually a -2.By associating the terms with a sign (+/-) you can shuffle them around in any order you like as far as addition/subtraction comes into it, as effectively you're just adding negative numbers along with the positive ones Quote Link to comment Share on other sites More sharing options...
JT! Posted February 8, 2013 Report Share Posted February 8, 2013 (edited) No because it would look like (2-2) + 10. There is no possible way bidmas would give you 12 from that equation, no matter how you write it. 12?! The answer is either 10 or -10 depending on how you look at it. When I talk about the 12 I'm talking about the 2 plus the 10. 4x2/4-2+10=4x0.5-2+10= 2-2+10= 2-12= -10 The bold shows the order that I calculated it according to bodmas. The thing I don't get is how you can say 'this actually equals 10' when bodmas is a rule that you can't ignore, so it actually equals -10. You can ignore bodmas. The fundamental problem with it is that bodmas states that division and addition have priority over multiplication and subtraction. When in fact they do not. Multiplication and division have the same priority and should be worked left to right, then after that same with addition and subtraction. Hence the answer to my example is 10, not -10 because you would do the 2-2 first before adding the 10. Edited February 8, 2013 by JT! Quote Link to comment Share on other sites More sharing options...
JT! Posted February 8, 2013 Report Share Posted February 8, 2013 You're on the right sort of lines, but you've actually got: (+2) + (-2) + (+10) You're not adding the 2 and 10, as that 2 is actually a -2. By associating the terms with a sign (+/-) you can shuffle them around in any order you like as far as addition/subtraction comes into it, as effectively you're just adding negative numbers along with the positive ones I get it now, I still think if you're working with bodmas you'd still add the 2 and the 10 together regardless of all that, I mean bodmas specifically tells you to do the addition first not matter how contradictory it is. But yeah just goes to show how bad bodmas is as a teaching technique. Quote Link to comment Share on other sites More sharing options...
Revolver Posted February 8, 2013 Report Share Posted February 8, 2013 When in fact they do not. Multiplication and division have the same priority and should be worked left to right, then after that same with addition and subtraction. Hence the answer to my example is 10, not -10 because you would do the 2-2 first before adding the 10. That does ring a bell, actually. It's been so long since I was in a maths class. Quote Link to comment Share on other sites More sharing options...
showurcolours Posted February 8, 2013 Report Share Posted February 8, 2013 Someone needs to close this thread asap. Quote Link to comment Share on other sites More sharing options...
JT! Posted February 8, 2013 Report Share Posted February 8, 2013 Why? Clearly the best thread on TF this year! Quote Link to comment Share on other sites More sharing options...
manuel Posted February 8, 2013 Report Share Posted February 8, 2013 I mean bodmas specifically tells you to do the addition first not matter how contradictory it is. Ummm actually no. Addition AND subtraction are equal and given the way the operations work it makes no effing difference. f**k me this thread is retarded. 1 Quote Link to comment Share on other sites More sharing options...
JT! Posted February 8, 2013 Report Share Posted February 8, 2013 So -10 and 10 have no difference? Quote Link to comment Share on other sites More sharing options...
manuel Posted February 8, 2013 Report Share Posted February 8, 2013 Ok do the sum 1+2-3+4-5+6 If you get the wrong answer like last time it's because you are inventing brackets that aren't there. Also, in bodmas or whatever you want to call it, addition has an equal rank to subtraction. You can't do one then make up a set of brackets and do the other. Quote Link to comment Share on other sites More sharing options...
JT! Posted February 8, 2013 Report Share Posted February 8, 2013 Ok do the sum 1+2-3+4-5+6 Acording to bodmas. 1+2-3+4-5+6 (1+2)-(3+4)-(5+6) (Addition first) 3-7-11 = -15 But the correct answer would be 5. Quote Link to comment Share on other sites More sharing options...
manuel Posted February 8, 2013 Report Share Posted February 8, 2013 Acording to bodmas. 1+2-3+4-5+6 (1+2)-(3+4)-(5+6) (Addition first) 3-7-11 = -15 But the correct answer would be 5. Ummmm you've invented a set of brackets there .... Also see my edit Quote Link to comment Share on other sites More sharing options...
JT! Posted February 8, 2013 Report Share Posted February 8, 2013 Yeah I added the brackets to show my working, basically doing the addition first before any of the subtraction. Quote Link to comment Share on other sites More sharing options...
manuel Posted February 8, 2013 Report Share Posted February 8, 2013 B Brackets first O Orders (ie Powers and Square Roots, etc.) DM Division and Multiplication (left-to-right) AS Addition and Subtraction (left-to-right) Left to right my good man. Bodmas is fine - you just aren't doing it right 1 Quote Link to comment Share on other sites More sharing options...
JT! Posted February 8, 2013 Report Share Posted February 8, 2013 Well this is what I'm saying, how's anyone supposed to know that DM and AS are grouped together as pairs and B and O aren't. When I got taught it we were never told of that... I bet if you posted my example to facebook and told people to use BODMAS to solve it most people would give the answer -10. Quote Link to comment Share on other sites More sharing options...
monkeyseemonkeydo Posted February 9, 2013 Report Share Posted February 9, 2013 I bet if you posted my example to facebook and told people to use BODMAS to solve it most people would give the answer -10. I'll take that bet. On this subject you're way too close to the American stereotype I'm afraid! Maybe there needs to be an example based on guns, ammunition and burgers... 1 Quote Link to comment Share on other sites More sharing options...
Nannerman Posted February 9, 2013 Report Share Posted February 9, 2013 I step away from this thread for two days. I have lost faith in this world. If you never learned how to properly use order of operations, don't argue about it. Quote Link to comment Share on other sites More sharing options...
JT! Posted February 9, 2013 Report Share Posted February 9, 2013 Well, look, we're talking about the correct way to do something wrong. I wasn't taught anything other than those specific orders of operations, and I only found out from a question like this a couple of years back that multiplication / division and addition / subtraction have the same priority and should be worked left to right. Was everyone else taught that at school with he orders of operation? Quote Link to comment Share on other sites More sharing options...
Luke Rainbird Posted February 9, 2013 Report Share Posted February 9, 2013 You should have been, assuming you had teachers that met the standard for qualification, were smart enough to get that far and paid attention.Of course all of the above are not often the case Quote Link to comment Share on other sites More sharing options...
JT! Posted February 9, 2013 Report Share Posted February 9, 2013 Shit, our math teacher was Irish and couldn't understand a word he said. Quote Link to comment Share on other sites More sharing options...
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