Jan 24, 2010
107
0
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Status
Pre-Dental
(1/6) * (3/4) - (5/3) + (1/12) =

I know this seems like a really easy question but I think top score has the wrong answer to it. According to PEMDAS addition comes before subtraction. The answer that top score gives makes subtraction come before addition.

The answer key says the answer is -35/ 24

This is what I did

MULT- (1/6) * (3/4)= 3/24
ADDITION- (5/3) + (1/12)= (MAKE LCD 24) =(40/24) + (2/24) = 42/24

NOW SUBTRACTION- (3/24)- (42/24)= -39/24

TOP SCORE DOES THIS:
3/24 - 40/24= -37/24

Then addition
-37/24 + 2/24= -35/24

Am I wrong of is topscore right?
 
Jan 11, 2010
380
15
51
Status
The answer is -35/24
and here is what you did wrong :

you got 3/24 - 5/3 + 1/12
then you added 5/3 + 1/12 which is wrong. You should have done: -3/5 + 1/12
then add 3/24
you should be careful when there is a " - " sign before an expression
the best way is to go from left to right :
3/24 - 5/3 + 1/12
common denominator is 24

(3-40+2)/24 = -35/24
 
Jun 14, 2009
800
3
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Status
Pre-Dental
the "AS" in PEMDAS doesnt mean addition before subtraction. It means addition and subtraction from left to right. Likewise "MD" doesn't mean multiplication before division. It means multiplication and division from left to right.
 
Jan 24, 2010
107
0
0
Status
Pre-Dental
ohhhh so you go from left to right...pathetic how i've forgotten the basics lol.. thanks guys