Problems with signs law and other arithmetic operators

[Gerald H]

(04-07-2015 05:09 PM)DrD Wrote:  

(04-07-2015 04:36 PM)compsystems Wrote:  5++6 // error
5--6 // error

I get correct results for the two expressions that you've shown as error.

5+ +6 displays in history as 5+6, and Ans(1) = 11. (Note I inserted a space between the two plus signs, to clarify that the 6 has a positive symbol).

5--6 Uses the subtraction sign after the 5 and the negative sign preceding the 6 to also result in Ans(1)=11. It's not clear in this posting that the 6 has the negation symbol, from the [+/-] button, for example. However, the Prime display shows that the negation symbol is smaller than the minus symbol.

Not so on 50G - between ' ' two subtracts are allowed eg '5--6'.