Multiplying fractions is straightforward. We multiply the numerators together and the denominators together. A new fraction is obtained, which is the product.
Multiplying two fractions
||\frac{5}{8}\times\frac{7}{11}=\frac{5\times7}{8\times11}=\frac{35}{88}||
||\frac{1}{2}\times\frac{4}{5}=\frac{1\times4}{2\times5}=\frac{4}{10}=\frac{2}{5}||
Multiplying a fraction by a whole number
||\frac{2}{3}\times 4 = ?||
To multiply a whole number with a fraction, place the whole number over 1. Next, apply the multiplying fractions procedure as explained above: ||\frac{2}{3}\times \frac{4}{1}=\frac{8}{3}||
If the fractions have different signs, the method is the same as when multiplying two integers.
When multiplying mixed numbers, first convert the mixed numbers into fractions, and then perform the multiplication.
||4\dfrac{1}{2} \times 5\dfrac{1}{4}||
We convert the mixed numbers into fractions, as follows :
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For |4\dfrac{1}{2},| use the trick |4\times 2 + 1 = 9.| The result is |\dfrac{9}{2}.|
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For |5\dfrac{1}{4},| use the trick |5\times 4 + 1 = 21.| The result is |\dfrac{21}{4}.|
Now the fractions can easily be multiplied. ||\frac{9}{2}\times\frac{21}{4}=\frac{9\times21}{2\times4}=\frac{189}{8}||
The answer is |\dfrac{189}{8},| which is irreducible (in its simplest form).
However, we can convert the fraction into a mixed number which results in: |23\dfrac{5}{8}.|
Pour valider ta compréhension des fractions de façon interactive, consulte la MiniRécup suivante :
