Here are the filled-in blanks:
- Like terms - terms consisting of the same variables, raised to the same powers
- Simplifying - to combine all like terms in an expression using appropriate operations
- Algebraic expression - an expression made up of any combination of numbers, variables (letters or symbols), signs of operations, and grouping symbols
- Algebraic properties - properties used to rewrite expressions without changing their value, including the associative, commutative, and distributive properties