Ans

[Eduardo Silveira]

Thank you for answers, I didn’t really think about the help. But it’s a good point, the help is very good. That being said, the implementation chosen bu HP seem very strange to me, different from other calculators, and when I showed it to several users, they were all surprised by the result. It is important to keep in mind that when the user presses [+,-,*,/] they are trying to operate with the first level of the history and not with a value that has already been deleted. Also, when pressing [simplify], then it uses the history… well, mu two cents! Thanks again