operations with fractions


To add or subtract fractions we need them to have the same denominator, then we add or subtract the numerators:

If they haven’t got the same denominator, we reduce to common denominator:


To multiply fractions, we multiply the numerators and the denominators:



The inverse of a fraction is another fraction in which we have exchanged denominator  and numerator. If we multiply the fraction by its inverse we obtain 1:


To divide fractions:
- Multiply the numerator of the first fraction by the denominator of the second one and write the result in the numerator, and then multiply the denominator of the first fraction by the numerator of the second one, and write the result in the denominator.
- In another way, we can divide fractions by multiplying the first fraction by the inverse of the second fraction.


NOTE: Remember the hierarchy of the operations:
- Brackets first
- Powers and square roots
- Divide and multiply (work from left to right)
- Add and subtract 



  Exercise: Calculate:


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