You can use an arithmetic expressions in templates.
Use the following construction [&expression].
Example:
[&2*2] gives you 4.
Example:
[&<&data-224--mes?Value>/4] value stored in file "224.mes" divides on 4.
Expressions <&> are calculated earlier. Constructions later than arithmetic expressions calculating.
Admissible operations: -,+,/,* also logical: "==","!=","<" and ">".