According to the order of operations, you need to multiply first.
When you multiply into a fraction, the numerator (top number) changes.
In this case, you'd multiply the 7 by 4 to get 28.
To add fractions, they have to have the same denominator. (bottom number)
Let's find the lowest common denominator of 3 and 12.
Prime factorization of 3: 3
Prime factorization of 12: 2*2*3
Multiply all of these together, ignoring the duplicates.
2*2*3 = 12
How can we change 1/3 to have a denominator of 12?
Well, if you multiply or divide both the numerator and denominator of a fraction by the same number, it will stay equal. For instance, 1/2 = 2/4.
We want the 3 to become 12. That means we'd multiply by 4.
Multiplying 1 by 4 gives us 4.
Thus 1/3 = 4/12.
Now just add the numerators.
Since the top and bottom are both divisible by 2, we can simplify this by dividing them both by 2.
And again.
If you wanted that as an improper fraction, that would be