HP strange RPN operation??? I just find an odd behavior on my hp rpn operation. Can someone try the following sequence of entry and explain to me this strange behavior? Press 5 (any number will do). Press 'Enter' (this should duplicate 5 to x an y stacks) Press 'Enter' again (duplicate 5 again so now x,y and z stack are all 5) Press 'RDn' to rotate stack 4 times (this should bring the stack configuration back to the same, x,y and z stack are all 5. The stack should read (5,5,5,0) for (x,y,z,t). Now press 10 and then *. Normally, I would expect the stack to be (50, 5, 5, 0) for (X, Y, Z, T). But if you follow the above step, you will get (50, 5, 5 ,5). Am I missing something here?