How to evaluate the following prefix expression? Can you please help in evaluating following prefix expression? Thank you.
– ^ / + + 4 6 2 – 4 1 2 9

I put in brackets everywhere first, starting with each operation and enclosing two arguments
   – ^ / + + 4 6 2 – 4 1 2 9 
= (– (^ (/ (+ (+ 4 6) 2) (– 4 1)) 2) 9)

Generally the arguments are single digit numbers, apart from where the minus sign appears; in this case the result of the minus operation is an argument.
Hopefully from here it should be straight-forward to see what to do. One way would be to convert everything into infix notation;
 (– (^ (/ (+ (+ 4 6) 2) (– 4 1)) 2) 9)
= (((4+6)+2)/(4-1))^2 - 9
= 7

Or you could go through and evaluate the prefix operations one by one, like Gareth Ma's answer.
