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1.2 Rounding & Calculators

1.2 Rounding & Calculators
  • 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 4 divided by 6 as follows.

    4 divided by 6 = 2(cancelled) x 2 divided by 2(cancelled) x 3 = 2 divided by 3

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

    (27.985 tanks(cancelled)) times (11.9 gallons divided by 1 tank(cancelled)) equals 333.0215 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."

    equation showing worked out math detailing: Per means divide. Invert and multiply. Cancel out miles from numerator and denominator. The answer is 27.985 tanks

    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: 536 miles divided by 11.9 gallons is approximately 45 miles per gallong
    2. A 2011 Infiniti EX35: 342 miles divided by 20 gallons is approximately 17 miles per gallong
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