Least common denominator of the numbers in the list $-\frac{9}{10},\frac{11}{5},-\frac{13}{20}$ is $20$. Convert numbers in the list to fractions with denominator $20$.
$$-\frac{18}{20},\frac{44}{20},-\frac{13}{20}$$
To sort the list, start from a single element $-\frac{18}{20}$.
$$-\frac{18}{20}$$
Insert $\frac{44}{20}$ to the appropriate location in the new list.
$$-\frac{18}{20},\frac{44}{20}$$
Insert $-\frac{13}{20}$ to the appropriate location in the new list.
$$-\frac{18}{20},-\frac{13}{20},\frac{44}{20}$$
Replace the obtained fractions with the initial values.
