4. What is the value of the following prefix expression:

   + - *235 / * *234

where A**B = AB?

Hi math01-ga,

  Good day and thanks for your question.

The prefix expression 

[1]   + - * 2 3 5 / ** 2 3 4  ----> * 2 3 = 2 * 3 = 6
[2]   + - 6 5 / ** 2 3 4      ----> - 6 5 = 6 - 5 = 1
[3]   + 1 / ** 2 3 4          ----> ** 2 3 = 2 ** 3 = 8
[4]   + 1 / 8 4               ----> / 8 4 = 8 / 4 = 2
[5]   + 1 2                   ----> + 1 2 = 3
[6]   3                       ----> Answer


Hence your final answer is 3

The tree representation of this is [I hope this formats out properly]
            
              [+]
     
          /         \

       [-]           [/] 

      /   \         /   \
 
   [*]    [5]     [**]  [4]

  /   \          /   \
 
[2]   [3]      [2]   [3]


I hope this answers your question. If you have any clarifications,
please fell free to ask.

Thank you for using this service and have a nice day

Warm Regards,
aditya2k