- 1). See if the denominators of the two fractions are the same. If they are, the subtraction process is very simple. You first subtract the whole numbers and then you subtract the numerators. For example, in the equation 5 7/10 - 3 4/10, you would first subtract 3 from 5 to get 2 and you would then subtract 4/10 from 7/10 to get 3/10. The answer is 2 3/10.
- 2). Change mixed numbers to improper fractions first if the denominators are different. For example, in the equation 8 4/6 - 5 1/3, you must change each fraction into a mixed number. When you change 8 4/6 into an improper fraction, you multiply 8 * 6 to equal 48 and you add 4 to equal 52. The improper fraction is then 52/6. Change 5 1/3 into an improper fraction by multiplying 5 * 3 to equal 15 and then add 1 to equal 16. The improper fraction is 16/3. Now the equation is 52/6 - 16/3. The next step is to reduce the fractions to lowest terms. Reduce 52/6 to 26/3 and 16/3 is already in lowest terms. The equation is now 26/3 - 16/3. Subtract the numerators to get 10/3. Convert 10/3 to a mixed fraction by dividing 3 into 10 to equal 3 1/3. The answer to 8 4/6 - 5 1/3 is 3 1/3.
- 3). Convert denominators to make them match before subtracting, if necessary. After changing mixed numbers to improper fractions, if the denominators of the improper fractions are not the same, you must make them the same before subtracting. For example, 4 2/3 - 2 1/4 becomes 14/3 - 9/4. Before subtracting these fractions, you must have lowest common denominators. Multiply 14/3 * 4/4 to equal 56/12. Multiply 9/4 * 3/3 to equal 27/12. Subtract 27/12 from 56/12 to equal 29/12. Change 29/12 to a mixed number by dividing the denominator into the numerator (29 divided by 12) to equal 2 5/12. The answer to 4 2/3 - 2 1/4 is 2 5/12.
- 4). Convert the numerators to enable subtraction if necessary. For example, in the equation 7 1/4 - 2 2/4, change 7 1/4 to 6 5/4 and then subtract. Subtract 2 from 6 to equal 4. Subtract 2/4 from 5/4 to equal 3/4. The answer to 7 1/4 - 2 2/4 is 4 3/4.
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