How do math with values of variables through automation?

Question

I would like to automate a calculation through automation rule.

Here, I have a task having custom field = X (numeric)

X= (A+B)/C, where

A&C= custom field of Task

B= sum of custom fields of child of Task

Here, A&C are numeric values and B is calculated value created through app.

Now, B is not a field (only used for calculation purpose)

Option1 - Solution I have tried (didn't work):

* Created B as a field in Task
* Automated (A+B) and stored as variable x -  {{customfield_12345.Plus(customfield_23456)}}
* then x is divided by C and stored as variable y - {{x.divide(customfield_34567)}}
* display y in field X {{y}}

The rule run successfully. But no output as such.

Option 2 - The solution worked:

* Created B as a field in Task
* Created field D to get A+B (automation)
* X=D/C (automation)

Is there a way if I can go with option 1 without creating field B?

Mohammed Shakhib · Answer

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Cheers!

CarlosAntonio · Answer

You’re very close, the issue comes from how Jira treats created variables.

In automation, variables are stored as text, not numbers. So even if your rule runs successfully, math operations can fail or return empty unless you explicitly handle the type.

To make your Option 1 work without creating field B, you can use the advanced math expression instead of chaining variables:

{{#=}} ({{customfield_A}} + {{lookupIssues.customfield_B.sum}}) / {{customfield_C}} {{/}}

This way, you avoid intermediate variables and ensure Jira evaluates everything as numbers in one step.

In short, instead of storing A+B in a variable, calculate the full expression directly using {{#=}} syntax for reliable results.

Yi Meng · Answer

Thank you @Bill Sheboy  This works.