 the bottom numbers must be the same

And to put all the fractions with the same bottom number you must:

Multiply the top and bottom of each fraction by
the other fraction's bottom number

Note: There are many ways to add fractions but with Mammoth Memory, we propose this one method that suits every addition of a fraction. That way you only have one rhyming slogan to remember.

Example 1

5/9+1/9=(5+1)/9=6/9=2/3

This example the bottom numbers (denominators) are the same.

Example 2

3/8+5/6

Make the bottom denominator the same for both so multiply the top and bottom of each fraction by the other fraction's denominator.

3/8\times6/6+5/6\times8/8

NOTE:

6/6 or8/8=1

When multiplying anything by 1 it does not alter the fraction.

Therefore  3/8\times6/6=(3times6)/(8times6)=18/48

And

5/6\times8/8=(5times8)/(6times8)=40/48

18/48\+40/48=(18+40)/48=58/48

Now just make 58/48 simpler

58/48=29/24=1\5/24

Example 3

Work out 3/4+1/6

Make the bottom denominator the same for both so multiply the top and bottom of each fraction by the other fraction's denominator.

3/4\times6/6+1/6times4/4

NOTE:

4/4 or 6/6=1

Multiplying it by 1 does not alter it.

Therefore

3/4\times6/6=(3times6)/(4times6)=18/24

and

1/6\times4/4=(1times4)/(6times4)=4/24

18/24\+4/24=(18+4)/(24)=22/24
Now just make 22/24simpler
22/24=11/12