Its best to use the the map range node:
the input would be the slider value (bind on change value)
In range A is 0.0
In range B is 1.0
Out range A (the minimum value for the range your variable is using → in your case 70)
Out range B (the maximu value for the range your variable is using → in your case 100)
the Return value is then plugged into round for converting it back to integer
