<u><em>What you need to know:</em></u>
<u>product</u> - the answer you get when multiplying
<u>numerator</u> - the top number in a fraction
<u>denominator</u> - the bottom number in a fraction
<u>improper fraction</u> - a fraction where the numerator is a bigger number than the denominator
So let's start off with an example:
2
- 1
Because these are mixed fractions, we'll change them to improper fractions. We'll start with the first mixed fraction.
<u><em>Step 1:</em></u>
Multiply the whole number with the denominator of the fraction.
2
In this case, we'll be multiplying 2 and 4, which is 8.
<u><em>Step 2:</em></u>
Add the product with the <em>numerator</em>.
8 + <em>1</em> = 9
<u><em>Step 3:</em></u>
Place the number 9 into the numerator, <em>while still keeping the denominator the same:</em>

<u><em>Step 4:</em></u>
Repeat steps one through three for the second mixed fraction.
Now you have this:
- 
<u><em>Step 5:</em></u>
Find the least common multiple of the two fractions.
(Let me know if you don't know how to do this).
Your result should be:

<u><em>Step 6:</em></u>
Subtract across, <em>while still keeping the denominator the same:</em>
<em />
<em> = </em>
<em />
<u><em>(Only do if needed) Step 7:</em></u>
Simplify the fraction
Hope this helps, & if you have any questions, let me know!
Also, this is how I was taught to do it, and I'm not sure if there's a different way to solve it, but here's my work! :D