The word(s) "addition" appears 5 time(s) in 5 verse(s) in Quran in Mohsin Khan translation.

(1) The postponing (of a Sacred Month) is indeed an addition to disbelief: thereby the disbelievers are led astray, for they make it lawful one year and forbid it another year in order to adjust the number of months forbidden by Allah, and make such forbidden ones lawful. The evil of their deeds is made fair-seeming to them. And Allah guides not the people who disbelieve.

(2) And in some parts of the night (also) offer the Salat (prayer) with it (i.e. recite the Qur'an in the prayer), as an additional prayer (Tahajjud optional prayer - Nawafil) for you (O Muhammad صلى الله عليه و سلم). It may be that your Lord will raise you to Maqam Mahmud (a station of praise and glory, i.e. the honour of intercession on the Day of Resurrection.) .

(3) [Dawud (David)] said (immediately without listening to the opponent): "He has wronged you in demanding your ewe in addition to his ewes. And, verily, many partners oppress one another, except those who believe and do righteous good deeds, and they are few." And Dawud (David) guessed that We have tried him and he sought Forgiveness of his Lord, and he fell down prostrate and turned (to Allah) in repentance.

(4) And during a part of the night (also) glorify His praises (i.e. Maghrib and 'Isha prayers) and (so likewise) after the prayers [As-Sunnah, Nawafil - optional and additional prayers. And also glorify, praise and magnify Allah - Subhan Allah, Alhamdu lillah, Allahu-Akbar].

(5) And remembers (glorifies) the Name of his Lord (worships none but Allah), and prays (five compulsory prayers and Nawafil - additional prayers).