Question 6639
I would think that by "unit fractions", they would mean fractions having a numerator of 1.

So, I would separate the given fraction into the following:

{{{11/18 = 2/18 + 3/18 + 6/18}}} 

Now replace each of the new fractions with their eqivalent fractions by simplifying each one of them.

{{{2/18 = 1/9}}}
{{{3/18 = 1/6}}}
{{{6/18 = 1/3}}}

The three unit fractions are:

{{{1/9}}}, {{{1/6}}}, {{{1/3}}}