### 1.2 Rounding & Calculators

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• Math Help

When using unit analysis, the rules for "canceling" units are the same as they are for simplifying fractions. For instance, you can simplify as follows.

Similarly, when you multiply "tanks" by "gallons per tank," the "tanks" cancel out of the numerator and the denominator, leaving the answer as gallons.

To see why "miles" cancel out when you divide "miles" by "miles per tank," you can think back to a rule for dividing fractions. The rule states that "to divide by a fraction, invert and multiply."

Please work on this concept until it is crystal clear in your mind. Once you master unit analysis for both multiplying and dividing, you will have the power to make simple work out of the math in dozens of types of real-life problems.

• Consumer Suggestion

Are you in the market for a new or used car? What kind of car is right for you?

Use a search engine to search for the phrase "new and used cars." One of the many websites you will find is Kelley Blue Book. At this site, you can search by (just to name a few) make & model, car type, and price. You can even have a "Carfax Record Check" completed for a used vehicle you are interested in purchasing.

• Checkpoint Solution

To find the "miles per gallon" for each type of car, use the given information and divide.

1. A 2011 Toyota Prius:
2. A 2011 Infiniti EX35:

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