The term Rational Numbers refers to any number that can be written as a fraction.This includes fractions that are reduced, fractions that can be reduced, mixed numbers, improper fractions, and even integers and whole numbers. An integer, like 4, can be written as a fraction by putting the number 1 under it.Rational Numbers
When multiplying fractions, they do NOT need to have a common denominator.To multiply two (or more) fractions, multiply across, numerator by numerator and denominator by denominator.If the answer can be simplified, then simplify it.Example: Example:Multiplying Fractions
When multiplying fractions, we can simplify the fractions and also simplify diagonally. This isnt necessary, but it can make the numbers smaller and keep you from simplifying at the end.From the last slide:
An alternative:Simplifying DiagonallyYou do not have to simplify diagonally, it is just an option. If you are more comfortable, multiply across and simplify at the end.
To multiply mixed numbers, convert them to improper fractions first.Mixed Numbers
Convert to improper fractions. Simplify.Multiply straight across.Mixed Numbers
Try these on your own.Mixed Numbers
Remember, when multiplying signed numbers...Sign RulesPositive * Positive = Negative * Negative = Positive * Negative = Positive.Positive.Negative.
Multiply the following fractions and mixed numbers:Try These: Multiply
Solutions (alternative): MultiplyNote: Problems 1, 2 and 4 could have been simplified before multiplying.