Adding and subtracting fractional expressions will require you to examine their properties very specifically. Add and subtract fractional expressions with help from an experienced math professional in this free video clip.

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Adding and subtracting fractional expressions will require you to examine their properties very specifically. Add and subtract fractional expressions with help from an experienced math professional in this free video clip.

Part of the Video Series: Solving Math Problems

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Hi, I'm Ryan Ault. I'm a physicist and this is how to add and subtract fractional expressions. Now we have two expressions here, the first one is addition, the second one is subtraction. Just looking at the first expression we would like to add these two terms and we find that we have to match the bases so what we can do is multiply one term by the other term's base and vice versa. So for this example we simply have 3/3 and for the other term we have 7/7. Now multiplying these out we find 28/21 plus 3/21 and now that they have the same denominators we can add the numerators and we find that the expression becomes 31/21. Now we can do something almost identical for this term, the entire expression we find that we can multiply the 1/9 by 3/3 and the 2/3 by 9/9, carrying out the multiplication we find that it becomes 18/27 minus 3/27. Once again now that they have the same denominators we can subtract the numerators and we find that 18 minus 3 is 15/27. So remember the key part here is to make sure the bases match and in order to match them you multiply the numerator and the denominator of one term by the denominator by the other one. I'm Ryan Ault and this is how to add and subtract fractional expressions.