conversations.from: human
conversations.value: I need a clearer understanding of how to solve: At a certain grade level, three-fourths of students have a desktop computer at home. If 20 students do not have desktop computers, how many students are there at that grade level?
conversations.from: assistant
conversations.value: Twenty students represent 1 - 3/4 = 1/4 of the students at that level.
  So, there are 4 x 20 students = 80 students at that level.