Asrokhel Posted October 18, 2012 Share Posted October 18, 2012 If so, what is the answer to the following: (25 x 5) + 75 ? (20 ? 4) And, before you wonder, I am no longer in school, and haven't been for almost 20 years. Link to comment Share on other sites More sharing options...
bogas04 Posted October 18, 2012 Share Posted October 18, 2012 125 + 75 - 5 195 Link to comment Share on other sites More sharing options...
Astra.Xtreme Posted October 18, 2012 Share Posted October 18, 2012 (25 x 5) + 75 - (20 ? 4) 125 + 75 - (20 ? 4) 125 + 75 - 5 200 - 5 195 Link to comment Share on other sites More sharing options...
Bryan R. Posted October 18, 2012 Share Posted October 18, 2012 (25 x 5) + 75 ? (20 ? 4) Parenthesis always first 125 + 75 - 5 Left to right 195 Big b0b 1 Share Link to comment Share on other sites More sharing options...
Mulrian Posted October 18, 2012 Share Posted October 18, 2012 You could just type it into Google.... Japlabot 1 Share Link to comment Share on other sites More sharing options...
Big b0b Posted October 18, 2012 Share Posted October 18, 2012 If so, what is the answer to the following: (25 x 5) + 75 ? (20 ? 4) 125 + 75 - 5 200 - 5 195 And, before you wonder, I am no longer in school, and haven't been for almost 20 years. according to pemdas Parenthasis Exponents Multiplication Division Addition Subtraction. Link to comment Share on other sites More sharing options...
Japlabot Posted October 18, 2012 Share Posted October 18, 2012 You could just type it into Google.... Lazy man's method http://www.google.com/search?btnG=1&pws=0&q=(25+x+5)+%2B+75+-+(20+%2F+4) Link to comment Share on other sites More sharing options...
capr Posted October 18, 2012 Share Posted October 18, 2012 according to pemdas Parenthasis Exponents Multiplication Division Addition Subtraction. this kind of junk is EXACTLY the reason kids have trouble with this and adults who learned it this way don't know what they are doing years later. 10/5*2=4 NOT 1 Ambroos 1 Share Link to comment Share on other sites More sharing options...
Bryan R. Posted October 19, 2012 Share Posted October 19, 2012 this kind of junk is EXACTLY the reason kids have trouble with this and adults who learned it this way don't know what they are doing years later. 10/5*2=4 NOT 1 PEDMAS is correct. It is assumed that you know that Division/Multiplication is done left to right, then the same for Addition/Subtraction. If someone isn't able to remember that then there isn't much hope to begin with. Link to comment Share on other sites More sharing options...
David M Diller Posted October 19, 2012 Share Posted October 19, 2012 Please Excuse My Dear Aunt Sally. Link to comment Share on other sites More sharing options...
pack34 Posted October 19, 2012 Share Posted October 19, 2012 PEDMAS is correct. It is assumed that you know that Division/Multiplication is done left to right, then the same for Addition/Subtraction. If someone isn't able to remember that then there isn't much hope to begin with. If you get a different answer if you go left to right, or right to left then you're doing it wrong. Multiplication and division occur at the same time, not one after another. They are commutative so it doesn't matter. Link to comment Share on other sites More sharing options...
capr Posted October 19, 2012 Share Posted October 19, 2012 PEDMAS is correct. It is assumed that you know that Division/Multiplication is done left to right, then the same for Addition/Subtraction. If someone isn't able to remember that then there isn't much hope to begin with. The reason for little short things like PEDMAS is that we need them to help us remember. If I have to remember something that's not contained in PEDMAS then PEDMAS isn't doign it's job. It's like saying I need to remember to ring the green bell because that will help me remember to run the red bell. just remember to ring the red bell.... Link to comment Share on other sites More sharing options...
chconline Veteran Posted October 19, 2012 Veteran Share Posted October 19, 2012 If you get a different answer if you go left to right, or right to left then you're doing it wrong. Multiplication and division occur at the same time, not one after another. They are commutative so it doesn't matter. Uhh no. They have the same precedence over addition and subtraction, but if it occurs simultaneously, then you read from left to right. As another poster have mentioned, 10/5*2 = 4, not 1 -- this is a perfect example. Link to comment Share on other sites More sharing options...
-Himanshu- Posted October 19, 2012 Share Posted October 19, 2012 (25 x 5) + 75 ? (20 ? 4) =125+75-5 =200-5 =195 Link to comment Share on other sites More sharing options...
Bryan R. Posted October 19, 2012 Share Posted October 19, 2012 If you get a different answer if you go left to right, or right to left then you're doing it wrong. Multiplication and division occur at the same time, not one after another. They are commutative so it doesn't matter. The beautiful thing about math is that I can tell you with utmost certainty that you are wrong. Link to comment Share on other sites More sharing options...
CrashG Posted October 19, 2012 Share Posted October 19, 2012 2+2=Do your own homework....and be able to show how you got the answer. Somehow I doubt <this thread> counts as showing your work. If you've really been out of school for 20 years and still need the answer, you just might need to go back. Link to comment Share on other sites More sharing options...
aniv Posted October 19, 2012 Share Posted October 19, 2012 2+2=5 for extremely large values of two. Doli 1 Share Link to comment Share on other sites More sharing options...
nub Posted October 19, 2012 Share Posted October 19, 2012 So many idiots Link to comment Share on other sites More sharing options...
pack34 Posted October 20, 2012 Share Posted October 20, 2012 The beautiful thing about math is that I can tell you with utmost certainty that you are wrong. Nope. With order of operations BODMAS resolves the same solution as PEMDAS. The order of multiplication and division does not matter. How is this possible? (HINT: division is the multiplication of the reciprocal) When you're dividing you are simply multiplying by one divided by that number. Uhh no. They have the same precedence over addition and subtraction, but if it occurs simultaneously, then you read from left to right. As another poster have mentioned, 10/5*2 = 4, not 1 -- this is a perfect example. Wow... Remind me never to ask math questions on Neowin. (Subtraction is the addition of negative numbers) 10/5*2 (10/5 = 2) 2*2=4 10/5*2 2*(1/5) = 2/5 or 0.4 0.4*10 = 4 Ta freaking da Link to comment Share on other sites More sharing options...
.bin Posted October 21, 2012 Share Posted October 21, 2012 If you get a different answer if you go left to right, or right to left then you're doing it wrong. Multiplication and division occur at the same time, not one after another. They are commutative so it doesn't matter. Link to comment Share on other sites More sharing options...
Bryan R. Posted October 21, 2012 Share Posted October 21, 2012 Nope. With order of operations BODMAS resolves the same solution as PEMDAS. The order of multiplication and division does not matter. How is this possible? (HINT: division is the multiplication of the reciprocal) When you're dividing you are simply multiplying by one divided by that number. Wow... Remind me never to ask math questions on Neowin. (Subtraction is the addition of negative numbers) 10/5*2 (10/5 = 2) 2*2=4 10/5*2 2*(1/5) = 2/5 or 0.4 0.4*10 = 4 Ta freaking da 5*2=10, not .4. When you break down the problem to 10/(2*(1/5)), you leave no room for translation, which is great, but that's besides the point of the abbreviated order of operations. Link to comment Share on other sites More sharing options...
ArKeYa Posted October 21, 2012 Share Posted October 21, 2012 I'm surprised this doesn't have at least ten pages already. Guess because this been done before.... Link to comment Share on other sites More sharing options...
pack34 Posted October 21, 2012 Share Posted October 21, 2012 5*2=10, not .4. When you break down the problem to 10/(2*(1/5)), you leave no room for translation, which is great, but that's besides the point of the abbreviated order of operations. You're changing the problem mid way. When you rewrote it in this post you changed the "/5" to "*(1/5)" but kept that original division sign. 10/5*2 is the equivalent of 10*(1/5)*2. While "10/(2*(1/5))" is a different problem all together. Due to the commutative property of multiplication (order does NOT matter), You can start with "10/5" or "2/5" or "10*2". It simply does not matter. This is the big problem with representing math problems in a linear fashion. People assume brackets where there are none and end up getting the wrong answer not because they do not understand math but due to ambiguity of the problem. 5*2=10, not .4. 5*2 does not exist in the problem given. You are assuming parens where none are explicitly stated. Just becuase there is a division symbol in the middle of an equation does not mean that the entire left side of the problem is the numerator and the entire right side is a denominator It means the number being marked by the division symbol is being flipped to the denominator of the problem and being multiplied to it. The problem states 10/5*2 and not 10/(5*2). You are assuming parens where none are explicitly stated. If you wanted the five to be multiplied to the two then the five and two need to be parens. Link to comment Share on other sites More sharing options...
pack34 Posted October 21, 2012 Share Posted October 21, 2012 You're changing the problem mid way. When you rewrote it in this post you changed the "/5" to "*(1/5)" but kept that original division sign. 10/5*2 is the equivalent of 10*(1/5)*2. While "10/(2*(1/5))" is a different problem all together. Due to the commutative property of multiplication (order does NOT matter), You can start with "10/5" or "2/5" or "10*2". It simply does not matter. This is the big problem with representing math problems in a linear fashion. People assume brackets where there are none and end up getting the wrong answer not because they do not understand math but due to ambiguity of the problem. 5*2 does not exist in the problem given. You are assuming parens where none are explicitly stated. Just becuase there is a division symbol in the middle of an equation does not mean that the entire left side of the problem is the numerator and the entire right side is a denominator It means the number being marked by the division symbol is being flipped to the denominator of the problem and being multiplied to it. The problem states 10/5*2 and not 10/(5*2). You are assuming parens where none are explicitly stated. If you wanted the five to be multiplied to the two then the five and two need to be parens. As for the order of operations: Parens Exp MD (multiplication OR division) AS (addition OR subtraction) This is what we are taught in the US. In the UK and Canada they use BODMAS (notice how the division and multiplication are switched). Or even New Zealand whom simply uses PEMA. The division and subtraction abbreviations are completely left off of the mnemonic to hammer home that multiplication and division have the same level precedence as well as addition and subtraction. I believe that PEMA would be best way to teach the order of operations simply that the acronym itself takes into account equivalent precedence and doesn't arbitrarily place one before another. . Link to comment Share on other sites More sharing options...
Ambroos Posted October 21, 2012 Share Posted October 21, 2012 10/5*2 = 10 * (1/5) * 2 (= 4) There is only one fool-proof way to do these. Just split everything up and rewrite with the same symbol. Multiplication and division are exactly the same. As long as you make sure everything has the same symbol it doesn't even matter in what direction you do things. pack34 1 Share Link to comment Share on other sites More sharing options...
Recommended Posts