Beyond handshakes
http://illuminations.nctm.org/LessonDetail.aspx?ID=L631
A lesson plan for Grades 6–8 Mathematics
Using spreadsheets, students will explore another pattern, that of the triangular numbers. This exploration will enhance students’ ability to generalize a pattern with variables. Illuminations provides handouts and detailed instructions for completing the activity.
Students will:
- Understand the connections among the handshake problem, the triangular numbers, and the sums of positive integers.
- Use formulas to extend patterns in a spreadsheet, and graph those relationships.
NCTM Standards and Expectations:
- Represent, analyze, and generalize a variety of patterns with tables, graphs, words, and, when possible, symbolic rules.
- Relate and compare different forms of representation for a relationship.
- Use symbolic algebra to represent situations and to solve problems, especially those that involve linear relationships.
- Model and solve contextualized problems using various representations, such as graphs, tables, and equations.
North Carolina Curriculum Alignment
Mathematics (2004)
Grade 6
- Goal 5: Algebra - The learner will demonstrate an understanding of simple algebraic expressions.
- Objective 5.01: Simplify algebraic expressions and verify the results using the basic properties of rational numbers.
- Identity.
- Commutative.
- Associative.
- Distributive.
- Order of operations.
- Objective 5.02: Use and evaluate algebraic expressions.
- Objective 5.03: Solve simple (one- and two-step) equations or inequalities.
- Objective 5.04: Use graphs, tables, and symbols to model and solve problems involving rates of change and ratios.
- Objective 5.01: Simplify algebraic expressions and verify the results using the basic properties of rational numbers.
Grade 7
- Goal 5: Algebra - The learner will demonstrate an understanding of linear relations and fundamental algebraic concepts.
- Objective 5.01: Identify, analyze, and create linear relations, sequences, and functions using symbols, graphs, tables, diagrams, and written descriptions.
- Objective 5.02: Translate among different representations of algebraic expressions, equations and inequalities.
- Objective 5.03: Use and evaluate algebraic expressions, linear equations or inequalities to solve problems.
Grade 8
- Goal 5: Algebra - The learner will understand and use linear relations and functions.
- Objective 5.01: Develop an understanding of function.
- Translate among verbal, tabular, graphic, and algebraic representations of functions.
- Identify relations and functions as linear or nonlinear.
- Find, identify, and interpret the slope (rate of change) and intercepts of a linear relation.
- Interpret and compare properties of linear functions from tables, graphs, or equations.
- Objective 5.03: Solve problems using linear equations and inequalities; justify symbolically and graphically.
- Objective 5.01: Develop an understanding of function.



