Definition
Addend
A number or expression that is being added to other parts of an addition.
What it means
Look at the parts separated by plus signs. Each part is an addend. You can change the order of the addends without changing the sum.
Remember it
Addends are the parts you add; the sum is what they make.
Example
In 18 + 7 + 5 = 30, the addends are 18, 7, and 5. Their order can change, but their sum stays 30.
Watch for
In 18 + 7 = 25, 25 is the sum, not an addend in that equation.
Common mix-up
An addend is a part of an addition expression; the answer produced by adding is called the sum.
Exact meaning
An addend is a number or expression being added; an addition expression has two or more addends whose result is the sum.