Solve: $\frac{1}{4}+\frac{2}{4}+\frac{9}{4}$

Write five pairs of fractions whose sum is $1$. For example,

$\frac{1}{2}+\frac{1}{2}=1$ and $\frac{3}{5}+\frac{2}{5}=1$

What should be added to the following to get $1$.

$\frac{3}{8}$

What should be added to the following to get $1$.

$\frac{1}{9}$

What should be added to the following to get $1$.

$\frac{4}{5}$

What should be added to the following to get $1$.

$\frac{11}{15}$

What should be added to the following to get $1$.

$\frac{8}{35}$

What should be added to the following to get $1$.

$\frac{81}{100}$