(Need Help) Table cannot edit

Hi,

I'm newbie on AutoCad, and I'm on progress to study AutoCad. I found some problem n my study. I get task from my boss to edit drawing. I'm asked to change "Code No." on file from "2106838-01" to "2106838-02". But, when I doubleclick cell which containt "2106838-01", it's show value "6" not  "2106838-01". Can any expert explain and give me solutions?

Thank you

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