Hi, Thabang.

It is not possible to add a "has to be less than 100" as part of a Formula Column,

because in the Formulas of our Plugin, you can only use Basic math operations.

I just made a Test, for example, if i try something like this :

(columnA * columnB) <100

Then the Formula will 'sanitize' the "less than" symbol, since it is not a basic math operation.

But there is a workaround to achieve this in a table.

For example, you can add a Conditional Rule to this Formula Column,

something like :  if the value in any cell gets higher than 100, then transform  the content of the cell to ( any text you like) :

"Error. This value must not be higher than 100".

Here is an example screenshot how i made this Rule on my Formula Column :

You can see more about our Conditional Formatting, and all the available options you can use there.

https://wpdatatables.com/documentation/table-features/conditional-formatting/

Let me know if that helps.