To add fractions, you have to have a common denominator. You multiply 2 to 2 1/2, and to do this, you have to convert the mixed fraction into an improper fraction because you cannot add mixed fractions.
To convert a mixed fraction into an improper fraction, you multiply the whole number by the denominator and add it to the numerator:
2 x 2 = 4 + 1 = 5
and that number becomes the numerator: 5/2.
Now, you can multiply both the numerator and denominator by 2 in order to add it to 2 1/2.
Numerator: 5 x 2 = 10
Denominator: 2 x 2 = 4
=10/4
Now, you have to add this to (-1 3/4), but (-1 3/4) is a mixed fraction, so you have to convert it into an improper fraction as well. Ignore the negative sign.
1 x 4 = 4
4 + 3 = 7
=7/4
It was originally a negative, so add the negative sign: -7/4
Now you can add the two improper fractions together.
10/4 - 7/4 [when adding a negative to a positive, it is easier to move the two numbers around so that you are simply subtracting from a positive number. I applied this here. Originally, it may be written as: (-7/4) + 10/4.]
10 - 7 = 3. You don't subtract the denominator.
the answer is 3/4.
