One way of expressing $10$ as a combination of five $9\text{'}$s is $9+\frac{99}{99}=10$. Find the further ways of doing so. 

A clock takes three seconds to strike $3 \mathrm{O}\text{'}$ clock. How long does it take to strike $6 \mathrm{O}\text{'}$ clock? 

Write $1$ by using all the ten digits.

Write $10$ with five $9\text{'}$s. Do it in at least two ways?