Mail Time

If you add a letter to me,

I am the same.

If you remove a letter from me,

I still remain the same.

 

What am I?

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Housekeeping Note: I originally saw this riddle on the Kathy Lee and Hoda Show. If you know the answer, leave it in the comments below.

(Hint: look at the title)

Answer can be found in the Housekeeping Note of next week’s post The M&M Trick.