A fraction with a numerator greater than one can be written as
the sum of other fractions with smaller numerators.
The fraction strip is divided into six equal parts, so each part represents $\frac{1}{6}$.
The shaded parts of the model can be separated into one fraction strip with one part shaded and two fraction strips with two parts shaded.
$\frac{1}{6}$ 

$\frac{2}{6}$ 

$\frac{2}{6}$ 

So, $\frac{1}{6}+\frac{2}{6}+\frac{2}{6}$ is equal to the fraction modeled in the question.
To find the sum of fractions with a common denominator, add the numerators and leave the denominator the same.
Find which two fractions have a sum that equals $\frac{11}{12}$.
The two fractions that have a sum that equals $\frac{11}{12}$ have numerators whose sum equals 11 and denominators that are 12.
In the expression $\frac{5}{12}+\frac{6}{12}$, the sum of the numerators is 5 + 6 = 11, and the denominators are 12.
So, $\frac{11}{12}$ is equal to $\frac{5}{12}+\frac{6}{12}$.