Hello.
Fractions can be added and subtracted only if they are like fractions.
Example:
[tex]\mathrm{\displaystyle\frac{5}{9} -\frac{4}{9} =\frac{1}{9}}[/tex]
We can subtract these fractions because they are like fractions (they have the same denominator)
Another Example:
[tex]\mathrm{\displaystyle\frac{4}{9} +\frac{3}{9} =\frac{7}{9}}[/tex]
We can add these fractions because they are like fractions.
Therefore, the answer is "like"
I hope it helps.
Have a nice day.
[tex]\boxed{imperturbability}[/tex]
