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How to subtract fractions with different denominators

Want to find out how to subtract fractions with different denominators? We've provided a step-by-step guide of how to subtract fractions with different denominators to teach you everything you need to know.

Step 1: Find the least common denominator

Find the least common denominator (LCD) of the fractions. The LCD is the denominators’ least common multiple.

Step 2: Find the equivalent fraction

Find the equivalent fraction of each fraction so that they all have the LCD as the denominator.

Step 3: Subtract the new numerators

Subtract the new numerators and write the LCD as the denominator.

Step 4: Simplify if necessary

Reduce the difference to its lowest terms.

Examples of how to subtract fractions with different denominators

Q1) Find the difference of the following sets of fractions:

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Express the fractions with their equivalents so they share common denominators using the LCD.

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Subtract the numerators and write down the LCD as the denominator.

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Check if the difference is already reduced to its lowest terms.

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Q2) Jonathan needs to cover 3/4 mile as part of his daily run. If he has already covered 5/12 miles, how far must he need to cover to meet his required distance?

We want to find the difference of 3/4 and 5/12 to determine the remaining distance.

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Express the fractions so they have 12 as their denominator.

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Subtract the numerators to find the difference.

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Simplify to find the final answer.

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This means that Jonathan needs to cover 2/3 mile more to meet his practice requirement.