Answer :

konrad509
[tex]1-\frac{1}{9}-\frac{1}{2}=\\ \frac{18}{18}-\frac{2}{18}-\frac{9}{18}=\\ \frac{7}{18} [/tex]
AL2006
How much of the circle is clear ?  1/2 of it and 1/9 of it.
How much of it is (1/2 + 1/9) ?

Before you can add fractions, they need to have the same denominator.
The least common multiple of 2 and 9 is 18, so that's a good choice.

1/2 = 9/18

1/9 = 2/18

(1/2 + 1/9) = (9/18 + 2/18) = 11/18 .  That's how much of the circle is NOT shaded.

Since 11/18 of it is NOT shaded, the remaining 7/18 of it is shaded.