Ineed in my adding and/or subtracting fractions

First, you have to make sure that two fractions have the same denominator. he best way to do that is:
For Example:     4          7          8          7
                           +    =    +  
                         10        20        20        20

Then, just add or subtract the numerators and you got your answer.

Boom.

You can find the area of a rectangle by multiplying the length and height. so multiply 1/2*7/4(which is the simpler version of 1 3/4) and you get 7/8 as your answer.

Theres no drop down menu