How to perform operations on cura gcode variables?

[dlancep1 0]

Is it possible to perform operations on cura variables in start gcode?  For example if layer_0 is 65C, adding 5 to a variable like M190 S{material_bed_temperature_layer_0 + 5}.  This does not work, it shows M190 S65+5 when I look at the gcode and I want it to be M190 S70, but that gives an idea of what I'm trying to do.  If that is possible, what is the syntax to add +5 to the variable?

[obewan 37]

Not possible atm