Stats can be calculated from mathematical expressions that combine several other stats. In a previous example on the Mathematical Expressions article, we demonstrated how a stat called StrMod could be calculated using the current value of an existing Stat called Str.

This can be expanded to include expressions completely comprised of other stats.

Let's take a theoretical set of system rules where Strength and Agility are two Stats on a character. The combined value of those Stats makes up another Stat, called Fitness. Now we'll have another Stat called MaxHP, which is your Fitness score, multiplied by 5.

Let's make the value of Strength to be 2 and the value of Agility to be 3. These are each basic Stats.

Our first derived Stat will be Fitness. We'll write the value of Fitness to be {Strength + Agility}. Notice that when you make this change, the value of Fitness will become 5.

Our next derived Stat will be the Max HP score. So, for the Stat MaxHP, we will provide the value {Fitness * 5}.

For more information about using Stats and Actions, please check the Sheets documentation here:
Building Your Character with Stats and Actions