The title says (nearly) all. Write the digits $2$ $0$ $2$ $2$ in that order and apply mathematical operators to obtain all values from 0 to 9. What's allowed:
- The four basic operators, $+ - * /$
- Parenthesis to force the order of operations
- Power (like $2^0$)
- Factorial (like $2!$)
- Concatenation (like $202$)
- Square root ($\sqrt {}$)
- Digital point (with or without leading 0, like $2.02$ or $.2$)
- Periodic numbers (like $.\overline{2}$)
I did not need to use truncation.