Fraction Subtraction Calculator

Enter mixed or simple fractions for both values. Review LCD steps, improper forms, and decimals. Built for students, teachers, tutors, and fast accurate subtraction.

Enter Fractions to Subtract

Use whole numbers for mixed fractions. Leave the whole part at zero for simple fractions.

Subtraction uses the first fraction minus the second fraction. Choose the sign for each entry if the value is negative.

First Fraction

Second Fraction

Example Data Table

First Fraction Second Fraction Simplified Result Mixed Number Decimal
3 1/4 1 2/3 19/12 1 7/12 1.583333
5/6 1/4 7/12 7/12 0.583333
-2 3/5 1 1/5 -19/5 -3 4/5 -3.800000
7/8 -1/2 11/8 1 3/8 1.375000
4 2 5/6 7/6 1 1/6 1.166667

Formula Used

Fraction subtraction follows a common denominator approach. Mixed numbers are converted into improper fractions before subtraction.

a/b − c/d = (ad − bc) / bd
Using LCD L: a/b − c/d = [a × (L/b) − c × (L/d)] / L
Mixed number conversion: w n/d = (wd + n) / d

Method summary:

How to Use This Calculator

  1. Choose the sign for the first value.
  2. Enter the whole number, numerator, and denominator for the first fraction.
  3. Choose the sign for the second value.
  4. Enter the whole number, numerator, and denominator for the second fraction.
  5. Select the decimal precision you want in the output.
  6. Press Subtract Fractions.
  7. Review the simplified fraction, mixed number, decimal value, and step-by-step method above the form.
  8. Use the export buttons to save the calculation as CSV or PDF.

FAQs

1. Can this calculator subtract mixed fractions?

Yes. Enter the whole number, numerator, and denominator. The calculator converts each mixed fraction into an improper fraction before performing subtraction.

2. Does it simplify the final answer automatically?

Yes. After subtraction, the result is reduced to lowest terms using the greatest common divisor. You also see the mixed number and decimal forms.

3. Can I enter negative fractions?

Yes. Use the sign selector for each fraction. Keep the number fields non-negative and let the sign dropdown control whether the value is positive or negative.

4. What happens if one input is a whole number?

Leave the numerator at zero and keep the denominator as one or any valid value. The calculator treats the entry as a whole number automatically.

5. Why does the calculator use an LCD?

Fractions must share a common denominator before subtraction. The least common denominator keeps the numbers smaller and makes the subtraction steps easier to read.

6. Can I download the result?

Yes. After calculating, use the CSV button for spreadsheet-friendly output or the PDF button for a printable summary of the result details.

7. What if the result is greater than one?

The calculator shows both the simplified improper fraction and the mixed number form. This helps when the answer exceeds one whole unit.

8. Is the decimal answer exact?

The decimal output follows the precision you choose. Repeating decimals are rounded to that selected number of places for easier reading.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.