Looks like you totally ignored my reply at other question you asked.
If you need to interact with server to display value runtime, have a look here:
Did you look at this:
Localization of SSRS Reports[
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If you need to do write some code and get a complex caluculation done in report itself (and does not need to interact with server), then try
Custom Code option.
Go to Report Properties -> Code -> Write VB code here.
A sample tutorial on how to write and use custom code:
Embedded Code In Reporting Services[
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