Why my answer isn't making sense?

Question

 

1/2*3/1=3/2

3/4*3/1=9/4

1/3*2/1=2/3

 

The LCD is 12

3/2(6)=18/12

9/4(3)=27/12

2/3(4)=8/12

 

18/12+27/12+8/12=53/12

 

I can't get an answer that would add up to my equation.  I divided 12 in 53 and the answer was 4.41R8

Answer 1

1/2*3/1=3/2
3/4*3/1=9/4
1/3*2/1=2/3

Are you trying to add these quantities?

If so, the LCD is indeed 12; each quantity must be changed in such a way that the individual denominators all become12.

For 3/2, you must multiply by 6/6, giving 18/12

For 9/4, you must multiply by3/3, giving 27/12

For 2/3, you must multiply by 4/4, giving 8/12

 

Now you can add these three quantities; since all have denominator 12, the numerators can be added, giving

(18+27+8)/12 = 53/12.

To convert this improper fraction to a mixed number, we find that 53/12 gives quotient 4, remainder 5, so the answer is 4 + 5/12 which is usually written as a big 4 immediately followed by a smaller fraction 5/12.