Question

Please answer the following essay question:

Explain why we need to have a common denominator in order to add or subtract fractions.

Answer in paragraph form using complete sentences and include any calculations, graphs, and labeled diagrams as appropriate.

Answer 1

We need to have a common denominator in order to subtract different fractions because if we have an example like.

5/2 - 6/8 we cannot do that because the denominator is not alike.

We have to use multiplication to help us here.

2 x 8 = 16 !

So. no we have 5/16

so now we do 5 x 8 = 40

So now my new fraction is - 40/16 BUTTTT 40/16 is an improper fraction. so 40/16 = 5/2

Now we are back at the square 1 so now we have to fix 6/8.

8 x 6 = 48

6 x 6 = 36.

--

2 x 24 = 48.

5 x 24 = 120 or 12

now we have 12/48 and 36/48.

We can subtract now!

Hope this helped for problems like this.

Answer 2

Answer: The denominator of a fraction tells you the relative size of the pieces. Therefore, the reason fractions need a common denominator before adding or subtracting is so that the numbers of pieces you are adding/subtracting are all the same size.