For example, consider the expression DLG . Certainly you can multiply "the number of days a year" (180) by "the number of hours a week each girl listens to music" (18), but the product you get (3,240) doesn't have any interpretation in terms of the problem. In other words DLG doesn't really mean anything.
However some expressions do have a meaning. For example, in the expression Hm + Ho, in each term represents part of a students homework time. The sum represents the total time each student spends on homework. So the expression Hm + Ho is meaningful in the situation.
The phrase "the total number of minutes each student spends on homework each night" is a concise way to describe the number represented by Hm + Ho. We will call this concise description the summary phrase for the expression.
The list above tells us that each student spends 27 minutes on math homework, so Hm = 27, and that each student spends 52 minutes on other homework, so Ho = 52.
Therefore, Hm + Ho = 27 + 52 = 79, so each student spends 79 minutes a night on homework. But even if the numbers were different, Hm + Ho would still represent the number of minutes each student spends on homework each night.
Your Task
Your task is to come up with as many meaningful algebraic expressions as you can, using the symbols above. For each expression, do the following:
- Write the expression.
- Explain what the expression means, using a summary phrase.
- Give the numerical value of the expression, based on the values of the individual variables given in the chart.
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Career Connection to Teaching with Technology