Adendum or Addendum: How To spell?
The word Adendum is misspelled against Addendum, meaning "Something added, or to be added."
Addendum has double "dd" is mispronounced as "d"Remember double 'DD' in between the strings A & endum which should not be misspelled with single 'D'
Wrong Spelling:  A-d-endum  Correct Spelling:  A-dd-endum 
Check more misspelled words of Addendum to spell it correct.