how to difine global variable in Formula node?

[Eric99998]

I want to access the same vailable in different formula nodes, so I need to define a global or external vailables? How can I do this?

[RavensFan]

Formula Nodes are distinct environments from each other.  You will have to define the global constant in each node.  Or make it a variable and wire  your values to the variable input node on each of the formula nodes.

[smercurio_fc]

Corollary: What is your formula node doing? Perhaps it can be done just as well in pure G.