Addition And Subtraction Of Fraction

Addition and subtraction are basic operations in math. We can apply the same operations to fractions as well. But we have to check their denominators carefully beforehand. 

Addition and subtraction of like fractions (same denominators): 

Step 1: Check the given fractions, if denominators are the same or not.

Step 2: If denominators are the same, take the numerators of two fractions and add or subtract them.

Step 3: Give a final answer with the denominator.

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Addition and subtraction of unlike fractions (different denominators):

We can add or subtract only the same wholes. That’s the reason when adding unlike fractions, we make the wholes the same by making the denominator the same. Let’s see the steps in detail:

Step 1: Find the LCM of denominators. 

Step 2: Rewrite the fractions with a new denominator and multiply the numerator with the same number as in the denominator.

Step 3: Now add or subtract the numerators

Step 4: Write the answer. 

Step 5: Reduce the answer to its lowest form. This is the final answer. 

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Common errors:

  • Students at first, often when given a fraction to add or subtract will mistakenly add the numerator and the denominator across, for example, 1/2 + 1/5 = 2/5  or 1/5 – 1/3 = 0/2. Students are presenting that the fractions numerator and denominators are recognized as separate whole numbers.
  • Failing to find a common denominator when adding or subtracting fractions with unlike denominators.
  • Leaving the denominator unchanged in fraction addition and multiplication problems.