Math Review: Fundamentals of Math

Making Conversions | Keywords in Word Problems | Taking Percentages | Scientific Notation | Integers | Fractions | Decimals (including percents) | Ratios and Proportions | Units of Measurement and Conversions | Miscellaneous Problems

Making Conversions

Rates are essential when making conversions. Rates are used to compare different kinds of quantities. Rates on the test are either:

  1. found in the Conversions for Units of Measurement (for example 12 inches = 1 foot)
    OR
  2. defined in the problem. Comparisons of different kinds of quantities can usually be identified in a problem by the use of a preposition or prepositional phrase. Sixty miles per hour and 2 girls for every 1 boy are examples.

When making conversions, it is helpful to express these rates as fractions. For example, 12 inches = 1 foot can be expressed as

12 inches equals one foot or one foot equals twelve inches

The following formula gives one way to make conversions. This formula works well because it also allows for multiple conversions.

(quantity to be converted) x (rate or rates) = (converted quantity)

EX: Convert 48 inches to feet

convert 48 inches to feet

Note: Always set the rates up so like units cancel.

EX: Convert 10 kilometers to centimeters

convert 10 kilometers to centimeters

Note: We needed two rates here because there is no direct conversion between kilometers and centimeters.

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©2002, Last Updated: June 15, 2007
El Centro College
Communications, Mathematics, Developmental Studies, and Teacher Preparation Division