Basic math problem

• Jun 14th 2009, 06:57 AM
AnthonyC
Basic math problem
Good morning everyone.

I must first say that I am glad I found this website! There's a lot of good info here. I have a basic math problem that I can not solve.

1/16 - 3/4 + 15/8 =

Please note that the numbers above are fractions. The answer is 19/16. I had to cheat and look at the back of the book to get the answer. I still do not know how they came up with this. I've been trying to do this problem for the past 30 min. I know that the order of operation is PEMDAS:

Parentheses
Exponets
Multiplication (left to right)
Division (left to right)
Subtraction (left to right)

So from the order of operations, I would need to add 3/4 + 15/8 right? And what ever answer I get from there, add 1/16?
Any help would be appreciated.
• Jun 14th 2009, 07:11 AM
Quote:

Originally Posted by AnthonyC
Good morning everyone.

I must first say that I am glad I found this website! There's a lot of good info here. I have a basic math problem that I can not solve.

1/16 - 3/4 + 15/8 =

Please note that the numbers above are fractions. The answer is 19/16. I had to cheat and look at the back of the book to get the answer. I still do not know how they came up with this. I've been trying to do this problem for the past 30 min. I know that the order of operation is PEMDAS:

Parentheses
Exponets
Multiplication (left to right)
Division (left to right)
Subtraction (left to right)

So from the order of operations, I would need to do 3/4 + 15/8 first right? and what ever answer I get from there, subtract that from 1/16?
Any help would be appreciated.

$\displaystyle \frac{1}{16}-\frac{3}{4}+\frac{15}{8}$ (Make the demoninators the same first )

$\displaystyle =\frac{1}{16}-\frac{12}{16}+\frac{30}{16}$

$\displaystyle =\frac{19}{16}$
• Jun 14th 2009, 09:35 AM
miz.perfect84
Hi,
In school we were taught BODMAS, which i think is similar to PEMDAS
Brackets
Other
Division
Multiplication
Subtraction.

Anyway, what you need to do is find a common denominator for all three fraction, which in this case is 16. and make all three fractions the same with the common denominator,
So
1/16 will remain 1/16
3/4 will become 12/16 (multiply top and bottom by 4)
15/8 will become 30/16 (multiply top and bottom by 2)
Then apply BODMAS, so addition first and then subtraction.
so - 12/16 + 30/16 = 18/16 (dont forget the minus sign infront of the 12)
Then
1/16 + 18/16 = 19/16

I hope that makes sense
• Jun 14th 2009, 10:22 AM
AnthonyC
Thank you. 1-12+30 = -11+30= 19

I was doing... 1-12+30 = 11+30 = 40