How-Tos / Math

How to Subtract a Whole Number from a Fraction

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How to subtract a whole number from a fraction

Subtracting a whole number from a fraction might be tricky but this step by step guide helps you on how to subtract a whole number from a fraction easily.  

For Example,  \mathbf{\frac{3}{2} - 7}

Steps

  1. Convert the whole number into Fraction and Rewrite.

    \\\mathbf{\frac{3}{2} - 7} \\ \\\mathbf{\frac{3}{2} - \frac{7}{1}}

  2. Find the least common denominator (LCD) of the two fractions and multiply the numerator and denominator of the whole number fraction by LCD.

    \\\mathbf{\frac{3}{2} - \frac{7}{1}} \\ \\\mathbf{\frac{3}{2} - \frac{7*2}{1*2}} \\ \\\mathbf{\frac{3}{2} - \frac{14}{2}}

  3. Subtract the numerators.

    \\\mathbf{\frac{3}{2} - \frac{14}{2}} \\ \\\mathbf{\\- \frac{11}{2}}

  4. You can convert to a mixed number if you want.

    \\\mathbf{-\frac{11}{2} } \\ \\\mathbf{= - \ 11 \ % \2 } \\ \\\mathbf{= - \ 5 \ \frac{1}{2}}