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How do you add a fraction like 1/8 + 2/3? You can't make 3 a 8!!!!I dont get it????
5 Answers | add yours
High School Teacher
1/8 + 2/3 =?
First you have to find the LCM for the denominator. The Least Common Multiple (LCM) is the number that both denominators will go into evenly. The 8 and the 3 will both go into 24. You create improper fractions, 3/24 + 16/24 =? If you add the numerators 3 + 16 you get 19 so your answer is 19/24.
Posted by ladyvols1 on February 11, 2009 at 8:35 AM (Answer #1)
Middle School Teacher
Here's how you solve a problem like this.
You are right that 3 can't go evenly into 8 -- that would be too easy!! :-) If 3 went into 8, all you would need to do is change the 2/3 fraction into 8ths.
Since neither denominator fits evenly into the other, you need to change both fractions. The first step is to find the smallest number that they both go into evenly -- this number is called the LCM or Lowest Common Multiple. To find this, it's usually easiest to just go up the times table for the larger number til you find one that the smaller number also goes into. So, 8 x 1 = 8 (no help); 8 x 2 = 16 (no help); 8 x 3 = 24 (bingo! 3 also goes evenly into 24).
Now you know that you need to change both fractions into 24ths. To do this, multiply both top and bottom by the number needed to get to 24.
1 x 3 3
8 x 3 = 24
2 x 8 16
3 x 8 = 24
So, now you have two fractions you can add together:
3/24 + 16/24 = 19/24
You should always simplify your answer if you can, by dividing top and bottom by the same number. In this case you can't simplify since 19 is a prime number and so can't be divided evenly by any number other than itself and 1.
So, your final answer is 19/24
Posted by cburr on February 12, 2009 at 7:38 AM (Answer #2)
well to add 1/8+2/3 you have to find the common denominator that both 3 and 8 divide into without leaving a remainder. once you've done that then you change 1/8 and 2/3 to become numerators under the common denominator.
Posted by funkyboy on June 12, 2009 at 4:58 AM (Answer #4)
The best approach to use is to apply the knowledge of fractions.
These fractions have 8 and 3 as the denominators. If you want to add fractions, they must have the same denominator, thus the lowest common multiple of 8 and 3 is 24.
1/8 + 2/3 can be expressed as 1*3/24 + 2*8/24
it implies that 3/24 and 16/24 can now be added as they now have the common denominator 24.In adding fractions, you only add the numerators 3 and 16 which gives you 19.
Therefore your answer is 19/24.
Posted by givemoregurie on September 11, 2010 at 10:14 PM (Answer #5)
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