What's the expression for subtract 20 divided into fourths from 55 divided into fifths

Find the number of positive three-digit even integers whose digits are among 9, 8, 7,5, 3, and 1.

If you shift the linear parent function, f(x)=x, up 13 units, what is the equation of the new function?

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?