Why do fractions need to have a common denominator before you add or subtract them?

Question

this is a hard question.please help if posable.

Answer 1

When fraction do not have a common denominator, you are trying to add different sized pieces.  Remember that the smaller the denominator the larger the piece. 

So, to add or subtract fractions the pieces we are using must be the same size.

Answer 2

If you think of two pies, one cut into 3 pices and the other cut into 8 pices, if you want to take a slice away from each of them it would be unfair because the pie cut into 3 slices is not proportional to the one cut into 8 pices. This is how I think about it .

Answer 3

because it isNT posible now get out maiii face u ugly

Answer 4

because you do

Answer 5

ou can not add diffrent denomanators together with fractions you NEED a least common denomanator

Answer 6

Get off the Internet and rely on your Brain

Answer 7

UYGUIYTTUYTUGYFTYRYFYTRY

Answer 8

i'm not trying to be mean, but can't you just ask somboby, look it up on a another website, or just do nothing about it. if you're crying, i'm veryyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy sorry. i am to sad to tell you the anserws too.

Answer 9

The denominator tells you what size parts you are adding or subtracting.  The parts must be the same size when you add or subtract.