I am currently debating this with a friend...I know the order of operations is PEMDAS. (parenthesis, exponenents, multiplication and division, addition and subtraction). I say the answer is 9 (12+7)-(7+3) but he disagrees. Should it be 15 since addition and subtraction are grouped together in the order of operations rule? Please explain how you got your answer and why.
2006-09-30 08:21:56 · 17 answers · asked by Jess B 2 in Education & Reference ➔ Teaching
It's 15. BEDMAS is the order of operations, but with multiplication/division, and Addition/subtraction, you perform the pairs of operations in the order in which they appear, regardless of which of the two it is. So, if you had a questions with a multiplication, then a division, and another multiplication operation, you would do each one in order, despite the fact that division comes first in the BEDMAS acronym. Don't forget that when you have to answer a skill-testing question!
2006-09-30 08:29:54 · answer #1 · answered by poohmanchu3 2 · 0⤊ 0⤋
The answer is 15. (12+7 is 19 minus 7 is 12 plus 3 is 15)
You would be correct that the answer is 9 only if the original problem was (12+7)-(7+3); the reason being that they are two completely different equations.
In addition and subtraction the numbers may be added and subtracted in any order, as long as you keep the values the same, -7 HAS to stay -7. When a negative is added to a positive vs. two positives added together, the solution will be different because the values of the numbers are different (adding a negative to a positve is the same as subtracting). For instance, -(7+3)=-10, but -7+3=-4. Basically, you can't just throw in a parenthesis into a problem.
2006-09-30 09:17:28 · answer #2 · answered by s 3 · 0⤊ 0⤋
PEMDAS
incorporates the fact that either addition and subtraction or multiplication and division are each grouped together as one.
when doing addition or subtraction, you go from
12>+7=19>-7=12>+3=15
itx as simple as that.
u could do the same for.
i guess 12/6 x 3=
12/6=2 x 3=6
so sadly your friend is right.
but u can trick him/her using the divison.mulitplication method
chow =]]
â¥
2006-09-30 08:35:42 · answer #3 · answered by cookiemonster 2 · 0⤊ 0⤋
Addition and subtraction operations have the same precedence, in the absence of parentheses they are simply applied from left to right. So your sum is 12+7=19, -7=12, +3 = 15. I sincerely hope you are not a maths teacher!
2006-09-30 08:32:40 · answer #4 · answered by Sangmo 5 · 0⤊ 0⤋
15
2006-09-30 08:24:54 · answer #5 · answered by stashboxfull 2 · 0⤊ 0⤋
15 is the correct answer. You are interpreting the PEMDAS rule too literally. Addition and subtraction should be thought of as "equivalent" or "interchangeable" with respect to their order of operation (as should multiplication and division). If you want to think of constructing an english sentence out of PEDMAS, instead of putting "and then" between each of the terms, the "joining word" between "division" and "multiplication" and between "addition" and "subtraction" should be "and/or", i.e. Parentheses, and then exponents, and then multiplication and/or division and then addition and/or subtraction.
2006-09-30 09:12:42 · answer #6 · answered by Anonymous · 0⤊ 0⤋
The other thing you have to specify in the order of evaluation is which direction to evaluate when the same type of operation occurs in the formula. >Generally<, the order is left to right after priority of operations is resolved:
((12+7) -7) + 3 = (19-7) + 3 = 12 + 3 = 15
I think it's 15.
2006-09-30 08:37:05 · answer #7 · answered by spongeworthy_us 6 · 0⤊ 0⤋
the answer is 15, but you did it wrong
in pemdas, addition and subtraction are in the same step, and addition is NOT before subtraction, just work it out from left to right
2006-09-30 08:29:35 · answer #8 · answered by zrogerz69 4 · 1⤊ 0⤋
addition and subtraction have the same importance, therefore the question should be calculated as is, read from left to right. So the answer should be 15
2006-09-30 08:30:35 · answer #9 · answered by Anonymous · 0⤊ 0⤋
without the perenthesis its 15. with the parenthesis its 9 though because with the parenthesis you have to do 19-10, without them its just 12+7-7+3. you are right if the problem includes the perenthesis, but the problem in the bold question he is right.
2006-09-30 08:33:47 · answer #10 · answered by michelle 2 · 0⤊ 0⤋