Me. Jones has taken a survey of college students and found that 1 out of 6 students are liberal arts majors. If a college has 7000 students what is the best estimate of the number of students who are liberal majors

The exact answer is 1,166 (and two thirds, but surprise, you can't have two thirds of a person) which I got by dividing 7000 by 6. Simple stuff.

If you need an estimate though you could say something like 1,150, with the explanation that you knew 6 would go into 6000 one thousand times and then into the remaining 1000 about 150 times since a close benchmark, 5, would go in about 200 times, and then just added 1000 times to 150 times to get 1,150