Basic Algebra/Working with Numbers/Subtracting Rational Numbers

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Vocabulary[edit | edit source]

Lesson[edit | edit source]

Subtracting fractions when the denominators are equal is also easy

Notice that when the denominators are the same for either adding or subtracting fractions we only add or subtract the numerators. With this in mind we can now use the techniques learned in Lesson 4 to subtract more complex fractions by finding the factors of the following fractions

We can now see that multiplying 456 by 5 and 570 by 4 gives the smallest possible denominator

Now the question is, is this fraction irreducible? We know the factors in the denominator so checking if 361 is divisible by the numbers 2, 3, 5, 19 will show that 361/19 = 19 therefore

Which is now an irreducible fraction.

Example Problems[edit | edit source]

Practice Games[edit | edit source]

put links here to games that reinforce these skills

Practice Problems[edit | edit source]

(Note: put answer in parentheses after each problem you write)

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Adding Rational Numbers
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Multiplying Rational Numbers
Subtracting Rational Numbers