can someone please try and guess the correct answers for these questions 

 ? i wud really appreciate it ~
1) +16^(1/2) can be expressed  as a +ve  _______. It is _______
2)   10^(1/2) cannot be expressed as a _______ number, however it is a _______.
3)   6,7,9 and 15 are ______ numbers.  (real ?)
4) express non-terminating decimals
        a) 1/3
        b) 2