I have a calculation field in the parent table where I need to have an average of values in a field from the related records in a child table. But I need to only limit the calculation of the average to the LOWEST 5 values of the field FROM ONLY the last 10 records entered.

Is there a simple way to do this that I am missing?

I don't know about simple, but it could be done using a couple of custom functions.

The first function would get the values from the last 10 records (for this, the relationship needs to be left unsorted, or sorted by CreationDate or ChildID). In v.8.5, you could use the new List() function instead.

The second function would sort the 10 values, in ascending order. Then you would the take the first 5 values of the result and average them.

I'll give that a try, thanks.