# How do you add a fraction like 1/8 + 2/3? You can't make 3 a 8!!!!I dont get it????

cburr | Middle School Teacher | (Level 2) Associate Educator

Posted on

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.

ladyvols1 | High School Teacher | (Level 3) Senior Educator

Posted on

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.

jess1999 | Student, Grade 9 | (Level 1) Valedictorian

Posted on

Two add these two fractions you don't have to make the 3 into an 8. First, just find a common denominator which means a number that both the denominators can go into evenly. In this case it would 24.

so now, 1/8 has to be multiplied by 3/3 = 3/24

2/3 has to be multiplied by 8/8 = 16/24

now add the numerators together = 16/24 + 3/24 = 19/24

justifyapple | eNotes Newbie

Posted on

A method to solve question for adding fractions!

1/8+2/3

Karate Chop Method!

1.Mutiply the denominators,which I this case is 3 and 8, 3 times 8 is 24.There you got the denominators!

2.Now it is the numerators,mutiply these across.In this question,it 3 times 1 and 8 times 2.

3 times 1 is 3

8 times 2 is 16

3+16=19

BOOM!

malkaam | Student, Undergraduate | (Level 1) Valedictorian

Posted on

1/8 + 2/3

In order to add these both the denominator must be same and to do that we need to find the least common multiple, which can be found by listing the multiples of both numbers and finding the first common value,

8= 8  16  24

3= 3   6    9   12   15   18    21   24

24 is the least common multiple here, and we need to get both numbers to 24, we can do that by multiplying them with the number that will make them both 24.

(1/8) * 3

(2/3) * 8

3/24 + 16/24

crystaltu001 | Student, Grade 10 | (Level 1) Valedictorian

Posted on

1 / 8 + 2 / 3 is possible to answer. First off, you have to find a common denominator. What do 3 and 8 have in common? They can both multiply into 24. Then, the denominaor for both fractions become 24, but you have to change the numerators as well or else you wouldn't get the same worth as 1 / 8 and 2 / 3, so you multiply 1 by 3 because that's how you changed 8 to 24. Then, you multiply 2 with 8 because that's how you changed 3 to 24. From then on, it's 3 / 8 + 16 / 24, which ends up being 19 / 24.

Wiggin42 | Student, Undergraduate | (Level 2) Valedictorian

Posted on

1/8 + 2/3

A fast way is just to cross multiply the denominators and numerators by each other and then multiply the two denominators:

1 x 3 = 3
8 x 2 = 16
8 x 3 = 24

-->
`(3 + 16)/24`

19/24

acompanioninthetardis | Student, Undergraduate | (Level 1) Valedictorian

Posted on

since you cant make a 3 an 8, you find a common multiple of 3 and 8, (usually you get this by multiplying the two) so you would get 24 in this case, but remember what you do to the bottom you must do to the top so 1/8 and 2/3.

since we had to multiply 8 by 3, we multiply 1 by 3 giving us 3

and since we had to multiply 3 by 8, we multiply 2 by 8 giving us 16

so then you have

3/24+16/24= 19/24

zumba96 | Student, Grade 11 | (Level 3) Valedictorian

Posted on

1/8 + 2/3

Find the LCM

8x3=24

Multiply 1/8 by 3 and 2/3 by 8 and you should get

It should be

19/24

atyourservice | Student, Grade 11 | (Level 3) Valedictorian

Posted on

`1/8 + 2/3 `

you have to find the lowest common multiple for the denominators which would be 24, so multiply until it is 24

`1/8 xx 3 = 3/24`

`2/3 xx 8 = 16/24`

`3/24 + 16/24= 19/24`

givemoregurie | (Level 1) eNoter

Posted on

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.

revolution | College Teacher | (Level 1) Valedictorian

Posted on

Find the LCM  (lowest common multiple) of 8 and 3. That would be the denorminator of the fraction. The LCM of 8 and 3 is 24.

Just replace 8 and 3 with both 24 each.

1/8+2/3= 3/24+ 16/24

= 19/24

funkyboy | Student | eNotes Newbie

Posted on

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.