Adding fractions can be very simple. You just have to follow the rules.
Let’s take the following example:
1/2 + 1/5
What are the numerators of the above fraction? The numerators of the above fraction are 1 + 1
What are the denominators of the above fraction? The denominators of the above fraction are 2+5.
Are the denominators of the above fraction the same? The denominators of the above fraction are NOT the same. Before we can start adding the above fractions, we must make the denominators the same.
How do we make the denominators the same? We make the denominators the same by finding their Lowest Common Multiple or LCM.
How do we find the LCM of two numbers? We multiply the two numbers. So, in this case, the LCM of 2 and 5 = 2 X 5 = 10.
Now we know that 10 is the LCM of the two denominators of the fraction. It’s time to change the fraction to carry that denominator. Let’s go!
Let’s take our first fraction: 1/2. In order to change the denominator 2 into 10, we need to multiply 2 by how much? We need to multiply 2 by 5 in order to change it to 10.
The rule: whatever we do with the denominator, we must also do with the numerator, or the fraction would not be equivalent.
So if we multiply 2 by 5, we must also multiply 1 by 5. So then our new fraction is 5/10.
Following the same steps we can change the fraction 1/5 to 2/10.
So now our fractions become: 5/10 – 2/10
Let’s just add across. 5 + 2? 7.
In adding fractions, after following these steps, we just move across the denominator. So our answer then is 7/10
What is the sum of 1/2 + 1/5? Answer: 7/10
