Create separate Float and Integer variables, have the Slider affect the Float variable, and then use the Variable: Copy Action to copy the Float's value to the Integer. This will round down the Float's value to the nearest Integer. If the Menu uses AC as its Source, you can use the Slider element's Number of steps property to have it move by discrete values.
Using Unity UI as the Menu's Source, check the UI Slider component's Whole Numbers property. You can use a single Float variable, but it will then only have Integer values.
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There are two ways around this:
thanks!