# Thread: Can you tell me if i solved this right

1. ## Re: Can you tell me if i solved this right

This is simple manipulation of fractions.

$\frac {-1}{-3} + \frac 1 {-5} = \frac 1 3 + \frac {-1} 5$

To add these two fractions with different denominators you have to find the smallest common multiple of 3 and 5, which is 15. So:

$\frac 1 3 = \frac {1 \times 5}{3 \times 5} = \frac 5 {15}$

$\frac {-1} 5 = \frac {-1 \times 3}{5 \times 3 } = \frac {-3} {15}$

Hence:

$\frac 1 3 + \frac{-1 } 5 = \frac 5 {15} + \frac {-3} {15} = \frac 2 {15}$

2. ## Re: Can you tell me if i solved this right

Originally Posted by ebaines
This is simple manipulation of fractions.

$\frac {-1}{-3} + \frac 1 {-5} = \frac 1 3 + \frac {-1} 5$

To add these two fractions with different denominators you have to find the smallest common multiple of 3 and 5, which is 15. So:

$\frac 1 3 = \frac {1 \times 5}{3 \times 5} = \frac 5 {15}$

$\frac {-1} 5 = \frac {-1 \times 3}{5 \times 3 } = \frac {-3} {15}$

Hence:

$\frac 1 3 + \frac{-1 } 5 = \frac 5 {15} + \frac {-3} {15} = \frac 2 {15}$
*Face-palm* I don't how I missed that, I was over thinking and missing the basics..

Thank you so much ebaines, your helping me out big time!

3. ## Re: Can you tell me if i solved this right

Originally Posted by Urpes
All of that makes sense to me except for the $\frac 5 {15} + \frac {-3}{15}$ part

Where did those two come from?
What number does 3 and 5 go into? 15. You cannot add fractions without common denominators.

4. ## Re: Can you tell me if i solved this right

Originally Posted by Urpes
*Face-palm* I don't how I missed that, I was over thinking and missing the basics..

Thank you so much ebaines, your helping me out big time!
Oops. Did not see this post!

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