After typing 1/4 of a term paper on friday, richard completed 2/3 of the remainder on saturday. if he wanted to finish the paper that weekend what part was left to be typed on sunday?

of the paper

Explanation:
On Friday:
Richard finished 0.25 of the term paper.
This means that:
Remaining = 1 - 0.25 = 0.75 of the paper

On Saturday:
Richard finished  of the remainder.
This means that:
Richard finished 

Now, for Sunday:
We know that Richard finished 0.25 of the paper on Friday and  of the paper on Saturday.
This means that:
Total finished = 0.25 +  =  of the paper
If he wants to finish it by Sunday, then:
He needs to type = 1 - = of the paper

Hope this helps :)