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Math K-Plus

How To Subtract Fractions With Common Denominators And Unlike Denominators

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Learn Fraction Subtraction Math With Common Denominators Or Unlike Denominators





Fraction subtraction with the same denominator is very simalar to fraction addition. It is a three step procedure to get the final answer:
  • Add or subtract the whole numbers part of all fractions as required by their number sign to get the sum.
  • Since all the fractions have the same denominator, add or subtract (which ever is reqired) all fraction numerators to get the sum of the fractions.
  • Simplify the fractional sum and combine their result with the whole number sum.
  • You are now ready to practice Subtracting Fractions using our smart calculator. Try these examples: 6/15 + 4/15 =, (here is a difficult one) 3 1/11 + 27 6/11 =

Subtract Fractions With Common Denominators


79  -  19  = 

The Denominators Of Both Fractions Are The Same - Subtract Numerators (7 - 1)

(7 - 1)9  =  69

Simplify Answer Using Greatest Common Divisor

69  =  6 ÷ 39 ÷ 3  =  23




The alternative fraction subtraction problem is subtracting fractions with unlike denominator. It is a three step procedure to get the final answer:
  • Add or subtract the whole numbers part of all fractions as required by their number sign to get the sum.
  • Since some or all the fractions have different denominators, we must convert all fractions to have the same denominator before they can be added or subtracted together. This conversion is done by cross-multipying two fractions at a time to get common denominators or alternatively compute the Least Common Denominator; note when we cross-multipy, we are multiplying the fraction by the value one (1) e.g. 6/6 so the true value of the fraction is not changed. Once the denominator of all fractions are the same, perform the addition or subtraction of the numerators.
  • Simplify the fractional sum and combine its result with the whole number sum for the final answer.
  • You are now ready to practice Subtracting Fractions using our smart calculator. Try these examples: 6/5 - 2/10 =, (here is a difficult one) 13 1/7 - 3 6/7 =

Subtract Fractions With Unlike Denominators


74  -  56  = 

We Must Cross-Multiply Both Fractions To Get A Common Denominator

74  =  7 × 64 × 6  =  4224

56  =  5 × 46 × 4  =  2024

The Denominators Of Both Fractions Are Now The Same - Subtract Numerators (42 - 20)

4224  -  2024  =  2224

Simplify Answer Using Greatest Common Divisor

2224  =  22 ÷ 224 ÷ 2  =  1112





Recommended reading: Subtracting Fractions Calculator, How To Add Fractions, How To Multiply Fractions, and How To Divide Fractions.