Formula for updating a field with hundreds of options

[Atara_Rotenberg]

Hi,
we have a field in Marketo that is automatically populated with a number.  The number corresponds to one of our hundreds of our products.  Is the a way to have a formula in Marketo update a custom field. 
So if Field A=1, then Field B=aaa.  I understand how to do a change data value.
But how can I do it for hundreds at once?

Thank you!

[Alok_Ramsisaria]

You can create Field B as a Formula Field. The formula would be applied for one time, and will update automatically.