Each question states a total and how many units it took, and asks for the rate: 135 points in 9 games, 44 pages in 11 days, 40 dollars in 5 items. The answer is always how much per one.
Every division comes out exactly, because each question is built from its rate and multiplied up rather than drawn at random. A unit rate with a remainder is a different lesson, and it is not this one.
A rate with one on the bottom. 135 points in 9 games is a rate; 15 points per game is the unit rate. Reducing to per-one is what makes two rates comparable.
Divide the total by the number of units. 135 ÷ 9 is 15, so the rate is 15 points per game.
Because it is how you compare things that come in different sizes - price per item, miles per gallon, words per minute. It is the everyday use of ratio.
No. Each question is built from the rate, so the division is always exact. Rates that do not divide evenly are a decimals question.