From LimeSurvey Manual
Slider maximal value (slider_max)
When slider_layout is set, this question attribute sets the value of the right-end of the slider. By default, this value is set to 100. The expression manager can be used (without curly brackets) to set up a maximum value. However, please note that this value has to be calculated before the expression is displayed. For example, no custom value is displayed if the expression and the question and/or question answer codes used within the respective expression are displayed on the same page. If this happens, then the attribute will use the default value which is 100.
- Any number
- Expressions, without curly brackets.