An issue with negative number multiplication

[papatte]

Hi,
Thanks for you Calculator that evaluates math expressions.
I use it in my code, but I find a problem today with an expression, using Evaluate method:
I have the error "Invalid number for expression: Multiple" when the expression is "((5/9)x(-27.4-32))+273.15".
I reduced the expression to find where is the problem, and I got also this error with "2x(-3)" or "2x-3". But it's ok with the expression "-3x2".

Regards,
Patricia