Operations for Fractions


Adding,Subtracting,Multiplying,and Dividing Fractions



I'm going to show you how to add fractions in these videos.

Adding Fractions

This is a picture of Adding Fractions. Click on Adding Fractions to see a video on adding fractions.

Subtracting Fractions

  1. Click on Subtracting to see a video
  2. Put your fractions side by side
  3. If it has the same denominator then just subtract like normal.Don't subtract the denominators. For example if the fraction is 3/4 -2/4 then subtract to get 1/4
  4. If it has a different denominator then you have to change it to make it a common denominator.
  5. First, you have to find the least common denominator between the two.To find that you have to list the multiples of the two denominators and find the common one.
  6. My fractions are 3/4 - 1/3 so the least common denominator would be 12.
  7. Now you have to change 3/4 into an equivalent fraction with the denominator 12. So you multiply your denominator by a number to get to your new fractions denominator.
  8. I would multiply 4 and 3 to get to 12. You multiply the numerator with the same number you multiplied the denominator. I would multiply 3 and 3 to get to 9. My new fraction is 9/12.
  9. You do the same with your next fraction so that you would get the new fraction with the same denominator as the other one. I would get 4/12 when I multiply 1 and 3 by 4.
  10. Now you subtract your two new fractions. I would subtract 9/12 and 4/12 to get to my answer 5/12. If you are able to simplify it then simplify your answer. Also if its an improper fraction change it to a mixed number.
  11. That is how you subtract fractions.

Multiplying Fractions

  1. Click on Multiplying to see a song about multiplying fractions.
  2. Put your fractions side by side.
  3. Then just multiply across. If I had the fractions 3/4 and 1/3, I would multiply across and get 3/12.
  4. Then I would have to simplify to get 1/4
  5. The easy way is, you put your numbers side by side then look diagonally to see if the two numbers that are diagonal to each other has the same factors.
  6. When I look diagonally 1 and 4 does not have the same factors but 3 and 3 does. 3 and 3 can both be divided by 3 which would change them to 1.
  7. So since we simplified both your 3 and changed it to 1 just multiply your new fractions across.
  8. My new fractions are 1/4 x 1/1 which would get me to 1/4. This is the exact same thing I did before but this time I didn't have to simplify at the end.
  9. If you look diagonally and neither of your two numbers that are diagonal has the same factors then it means that it is already at its simplest form and all you have to do is just multiply across.
  10. This is how you multiply fractions.

Dividing Fractions

  1. This is how you divide fractions.Click on divide to see a song.
  2. You put your fractions side by side then you do the KCF.
  3. KCF stands for KEEP CHANGE FLIP. That means when you have two fractions for example 3/4 divided by 1/3.
  4. Then you KEEP the first fraction so I would KEEP 3/4.
  5. CHANGE the sign so I would CHANGE the sign from division to multiplication.
  6. FLIP the second fraction so I would FLIP 1/3 to 3/1.
  7. Now you multiply like normal. 3/4 x 3/1. That would get me to 9/4.
  8. Simplify if you need to and change it to a mixed number if it is improper fraction.
  9. I would divide the denominator from the numerator and the whole number is your answer and the remainder if there is one is going to be a fraction.The remainder is the numerator and the original denominator is the denominator.
  10. My answer is 2 and 1/4

Adding and Subtracting

This is a resource that will help with adding and subtracting fractions.

Multiplying Fractions

Dividing Fractions