Certify Teacher Practice Test

The correct choice accurately reflects that a symbol indicating a missing addend in an equation is termed a "Variable." Variables are often used in mathematical expressions to represent unknown quantities or values. In the context of addition, if an equation includes a symbol (like x or y) that signifies an addend that cannot be determined immediately, that symbol is categorized as a variable because it can take on different numerical values based on the equation's context.

The other terms do not appropriately describe a symbol that indicates a missing addend. An inequality refers to a mathematical statement that compares two expressions by showing that one is greater than, less than, or not equal to another. An expression is simply a combination of numbers, variables, and operations without an equality sign, but it does not specifically communicate missing information. The term "missing sum" is not a recognized mathematical term to describe a symbol, making it less relevant in this context. Thus, the use of the term "Variable" effectively captures the intended meaning of a symbol representing an unknown addend.