Addend
A quantity to be added to another, also called a summand. For example, in the expression a+b+c, a, b, and c are all addends. The first of several addends, or "the one to which the others are added" (a in the previous example), is sometimes called the augend.
See also
Addition, Augend, Plus, RadicandExplore with Wolfram|Alpha
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Cite this as:
Weisstein, Eric W. "Addend." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Addend.html