Often a relation in assembly will need to be made that supplies a value based on a suitable range of other dimensions. This is very much like If>Then or From>To structure.

The Setup area can do this.
Define the end value you want, and set it to formula.  The formula should be the driving dimension or equation.  Now access the rounding options, and choose 'by ranges'. 

Edit the ranges chart to reflect whatever from/to values you want to bridge, and then fill in the result.

Note:  A common use for Rounding by Ranges is to drive an array quantity.  In that case the numbers in the "value" area will be integers like 1, 2, 3.  Also for this case though be sure to set the 'Units' value of the row to 'none'.  (Keeping it at mm or inch will create a small problem with rounding values.)