Problem with polar form of complex numbers

[nikos92]

Hi this my first post here, so I am sorry if this isn't the right section to post my problem.
I have a HP Prime updated to latest SW version (12066) .
When I try to input a complex number in polar form with NEGATIVE angle (for example 20<-45 ...by the symbol < I mean the angle symbol located at multiply key "x" of hp prime when pressed same time with shift) I got back the error message: No significant digits in number. If the angle of the polar complex negative isn't negative there is no problem...also I can input without problem the complex number with negative angle when I am in CAS mode...but is there any way to overcome this problem out of CAS mode?

Thank's in advance for any help, have a nice day!!!