Multiply Fraction & a Whole Number
Multiply Fraction & a Fraction
Multiplying Mixed Fractions
Dealing with multiplying fractions examples may not be the hardest thing to do in Math.
But it’s still something that people do often have to take care when dealing with such sums.
Particularly if performing mixed fraction multiplication.
Multiplying a Fraction by a Whole Number:
The most basic multiplying fractions examples are when a fraction is multiplied with a whole number.
Like: 3 × \bf{\frac{3}{4}}
With such a sum, one just has to multiply the whole number by the numerator of the fraction.
Examples
3 × \bf{\frac{3}{4}} = \boldsymbol{\frac{3 \space \times \space 3}{4}} = \bf{\frac{9}{4}}
2 × \bf{\frac{5}{2}} = \boldsymbol{\frac{2 \space \times \space 5}{2}} = \bf{\frac{10}{2}} = 5
5 × –\bf{\frac{1}{4}} = \boldsymbol{\frac{5 \space \times \space -1}{4}} = \bf{\frac{-5}{4}}
Multiplying a Fraction by a Fraction:
When you are required to multiply a fraction by another fraction, things don’t work too differently.
The numbers on the top and bottom of the fractions both multiply each other.
Examples
(2.1)
\bf{\frac{1}{3}} × \bf{\frac{3}{4}} = \boldsymbol{\frac{1 \space \times \space 3}{3 \space \times \space 4}} = \bf{\frac{3}{12}} = \bf{\frac{1}{4}}
(2.2)
\bf{\frac{8}{5}} × \bf{\frac{7}{8}} = \boldsymbol{\frac{8 \space \times \space 7}{5 \space \times \space 8}} = \bf{\frac{56}{40}} = \bf{\frac{7}{5}}
(2.3)
–\bf{\frac{1}{2}} × \bf{\frac{4}{5}} = \boldsymbol{\frac{\text{-}1 \space \times \space 4}{2 \space \times \space 5}} = \bf{\frac{\text{-}4}{10}} = –\bf{\frac{2}{5}}
(2.4)
–\bf{\frac{2}{5}} × –\bf{\frac{5}{7}} = \boldsymbol{\frac{\text{-}2 \space \times \space 5}{5 \space \times \space \text{-}7}} = = \bf{\frac{\text{-}10}{\text{-}35}} = \bf{\frac{2}{7}}
Examples of Multiplying Fractions,
Mixed Fraction Multiplication
When it comes to mixed fraction multiplication, an effective approach is to convert the mixed fractions into improper fractions before performing the multiplication.
Then once the multiplication is complete, we can convert the result back to mixed fraction form.
The examples below show such situations.
Information on conversion from mixed fractions to improper fractions and vice versa can be seen on the Mixed Numbers and Fractions Page page.
Examples
(3.1)
1\bf{\frac{3}{4}} × 2\bf{\frac{1}{2}} = (\boldsymbol{\frac{1 \space \times \space 4 \space + \space 3}{4}}) × (\boldsymbol{\frac{2 \space \times \space 2 \space + \space 1}{2}})
= \bf{\frac{7}{4}} × \bf{\frac{5}{2}} = \bf{\frac{35}{8}} = 2\bf{\frac{3}{8}}
(3.2)
4\bf{\frac{1}{5}} × 3\bf{\frac{2}{7}} = (\boldsymbol{\frac{4 \space \times \space 5 \space + \space 1}{5}}) × (\boldsymbol{\frac{3 \space \times \space 7 \space + \space 2}{7}})
= \bf{\frac{21}{5}} × \bf{\frac{23}{7}} = \bf{\frac{483}{35}} = \bf{\frac{69}{5}} = 13\bf{\frac{4}{5}}
(3.3)
–1\bf{\frac{2}{3}} × 2\bf{\frac{1}{4}} = –(\boldsymbol{\frac{1 \space \times \space 3 \space + \space 2}{3}})  ×  (\boldsymbol{\frac{2 \space \times \space 4 \space + \space 1}{4}})
= –\bf{\frac{5}{3}} × \bf{\frac{9}{4}} = –\bf{\frac{45}{12}} = –\bf{\frac{15}{4}} = – 3\bf{\frac{3}{4}}
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