how to add/subtract two different fractions??

Sagot :

To add two different fractions; 
you need to find the "least common denominator"

for example:

1/2 + 1/4 =
The denominators 2 and 4 are not the same. You can't add directly. First find the least common denominator. To do this, ask to yourself which is the least multiple of 2 and 4.
Multiples of 2 = 2, 4, 8, 16
Multiples of 4 = 4, 8, 16, 31
Remember, find the "least." The least is 4. Do not use 8 because it is not the least. Do not use 2 because it is not common to 4.
So now use 4 as the denominator.
Make a huge fraction with 4 as the denomator then follow as directed;
Divide 4 to the first denominator that is 2.
 4 / 2 = 2.
Then multiply 2 to the numerator.
2 x 1 = 2.
Now you have your first numerator. Write 2 above your huge fraction then place an "add" sign.
Now, divide 4 to the second denominator that is 4.
4 / 4 = 1.
Then multiply 1 to the numberator of the fraction that is 1.
1 x 1 = 1.
Write 1 beside the addition sign.
Now you can add them properly- 2 + 1 / 4 = 3/4
Therefore; 1/2 + 1/4 = 3/4
It's actually a short process when you fully understand it.
get their lcd or least common denominator.. for example,.. you add 2/3 + 3/4.. you have to get the LCM of the denominator 3 and 4 which is 12.. then divide 12 with the denominator and multiply the answer to the numerator..

12÷3= 4, 4×2=8
12÷4=3, 3×3=9

so it becomes.. 8/12 + 9/12 = then add.. the answer is 17/12