### Standard 9: Algebra

In grades 5-8, the mathematics curriculum should include explorations of algebraic concepts and processes so that students can:
• Understand the concepts of variable, expression, and equation
• Benchmarks 9B (The Mathematical World: Symbolic Relationships)
Mathematical statements using symbols may be true only when the symbols are replaced by certain numbers.

Benchmarks 9B (The Mathematical World: Symbolic Relationships)
An equation containing a variable may be true for just one value of the variable.

• Represent situations and number patterns with tables, graphs, verbal rules, and equations and explore the interrelationships of these representations
• Benchmarks 2A (The Nature of Mathematics: Patterns and Relationships)
Mathematical ideas can be represented concretely, graphically, and symbolically.

Benchmarks 11B (Common Themes: Models)
Geometric figures, number sequences, graphs, diagrams, sketches, number lines, maps, and stories can be used to represent objects, events, and processes in the real world, although such representations can never be exact in every detail.

• Develop confidence in solving linear equations using concrete, informal, and formal methods
• Benchmarks 11C (Common Themes: Constancy and Change)
Things change in steady, repetitive, or irregular ways - or sometimes in more than one way at the same time. Often the best way to tell which kinds of change are happening is to make a table or graph of measurements.

• Investigate inequalities and nonlinear equations informally
Benchmarks 11D (Common Themes: Scale)
Finding out what the biggest and smallest possible values of something are is often as revealing as knowing what the usual value is.

• Apply algebraic methods to solve a variety of real-world and mathematical problems
• Benchmarks 11C (Common Themes: Constancy and Change)
Symbolic equations can be used to summarize how the quantity of something changes over time or in response to other changes.

Benchmarks 12D (Habits of Mind: Communication Skills)