Adenda or Addenda: How To spell?
The word Adenda is misspelled against Addenda, which is plural of "Addendum"
Addenda has double "dd" is mispronounced as "d"Remember double 'DD' in between the strings A & enda which should not be misspelled with single 'D'
Wrong Spelling:  A-d-enda  Correct Spelling:  A-dd-enda 
Explore spell check of Addenda to spell without errors.