addend
Pronunciation: /ˈadɛnd/
noun
Mathematics & Computing- a number which is added to another: as its name suggests the Accumulator ‘accumulates’ by keeping its addend in memory and incrementing by the addend it receives from another transmitting unitCompare with augend.

Origin:
late 17th century: from Latin addendus 'to be added', gerundive of addere (see add)