Something like this: [[(@{selected|Charisma} + @{selected|Wisdom})/2]] You can replace "selected" with a character's name. If you put this roll on a character sheet (say, in an ability), you can omit the "selected" or character name, entirely. This does require you to determine the highest/lowest. With the API (if you're playing in a game started by a Pro subscriber), MathOps could handle getting the highest and lowest attribute dynamically (with a max() and min() function): {& math (max(@{selected|Strength},@{selected|Dexterity},@{selected|Consitution},@{selected|Intelligence},@{selected|Wisdom},@{selected|Charisma}) + min(@{selected|Strength},@{selected|Dexterity},@{selected|Consitution},@{selected|Intelligence},@{selected|Wisdom},@{selected|Charisma}))/2}