Guess a number 1-10, multiply it by 2, now add with 54 and divide by 2. Lastly, subtract the number you guessed 1-10. What number are you left with, and what is unusual about it?

Create the number 24 using (all of) 1,3,4 and 6. You may add, subtract, multiply and divide. Parentheses are free.
You must use each digit only once.
Note that you may not "glue" digits together. Powers are not allowed.