Click the triangles!

## K-8

Selected curriculum materials for Middle School

Fractions: two visual representations, and a great problem to explore.

Number Pyramids, and In Addition: puzzles and problems whose only prerequisite is knowing how to add whole numbers

Before working in a high school, I taught elementary school for many years. This 1998 article summarizes some of my ideas on K-8 math education: Early Mathematics

A naked-eye astronomy unit: Look! Up in the Sky!

## Algebra

## About

- I designed some algebra manipulatives (the Lab Gear) and co-authored, with Anita Wah, an algebra textbook (
Algebra: Themes, Tools, Concepts-- ATTC). Start on these pages:- The Lab Gear
- ATTC

- A New Algebra: Tools, Themes, Concepts
- This article (published in the
Journal of Mathematical Behavior, v 12, #1, March 1993) summarizes much of the pedagogical and curricular thinking behind ATTC.

- Algebra for All?
- A short article on how the Lab Gear and ATTC help make the algebra course both more accessible and more mathematically rich.

- ATTC turned out to be somewhat controversial. Read the debates!
- My response to a critic.
- A discussion about geoboards.
## Basic

- Equations vs. Identities
- Three downloadable lessons from ATTC.

- Make These Designs
- A powerful activity about
y=mx+b, using any electronic grapher.

- Left or Right?
- Do these lines meet to the left or the right of the y-axis?

- Add Till It's Plaid!
- A lesson to connect graphical and algebraic approaches to systems of equations.

- Comparing Cell Phone Plans
- A "real world" application of linear functions and equations, in a fully spelled-out lesson.
## Intermediate

- Seeking Depth in Algebra 2
- An outline of some units, and links to some lessons.

- Parabolas and Quadratics
- Algebra 1 and Algebra 2 materials, plus some interesting follow-up lessons for teachers. Includes two non-standard proofs of the quadratic formula.

- Sequences and Series
- A dozen preview / introductory lessons on arithmetic and geometric sequences and series, from ATTC, plus a video on pedagogy and links to related materials.

- Exponential Functions
- A "real world" introduction, and a visual lesson about the graphs.

(Also: all exponential graphs are similar.)

- Iterating Functions
- A rich topic, which can serve as an introduction to sequences and series, and is prerequisite to the study of dynamical systems and chaos.

- Letters and Postcards
- An introduction to linear programming.
## Advanced

- Complex Numbers
- Games and worksheets, for Algebra 2 and/or Precalculus.

- Doctor Dimension
- A geometric/visual context to discuss rate of change and piecewise functions.
## All Levels

- Electronic Graphing
- Lessons on linear functions, equations and inequalities, quadratics, polynomials, exponential functions, logarithms, square roots, absolute value.

- Functions
- The Common Core State Standards include functions starting in 8th grade, and throughout high school. I have developed chunks of curriculum at all those levels.

- Function Diagrams
- A parallel axes representation, which provides a way to look at many familiar ideas from a fresh perspective. Includes many animations and worksheets, and ranges from middle school to calculus.

- Constant Sums, Constant Products
- An untraditional approach to several traditional topics, including the quadratic formula.
## Enrichment

- Introduction to Abstract Algebra
- A playful approach to group theory for a pre-college audience.

## Geometry

## Basic

- My book
Geometry Labs(Free download)- Three sample lessons:Angles
- An extension: Soccer Angles
An applet about the area of a circle.

- Background, links, activities, and articles on:
- Geometric Puzzles in the Classroom
- Books of related activities (all free downloads):
Polyomino Lessons- Three pentomino puzzle books
SuperTangram Activities, Books 1 and 2

SuperTangrams for Beginners, Books 1 and 2Tiling: links to tessellation activities, using manipulatives, grid paper, or working online.

## Intermediate

The Pythagorean theorem home page: applets, work on grid paper, activities on the geoboard.

- Notes and links on Transformational Geometry: some materials dircted to students, and some for teachers and curriculum developers.
- Isometries applets
Information about a book I co-authored with George W. Hart, about polyhedra and many other topics in two, three and four dimensions:

Zome Geometry(off site)

- Teaching Proof in high school
- Proofs "without words":
- Sum of angles in a triangle
- Pythagorean theorem
- Completing the square
- Parallelogram area
Construction (compass and straightedge basics, interactive geometry software puzzles, concurrence theorems)

## Advanced

- The geometry of graphs:
- y = mx + b. (Similar triangles and the graphs of linear functions)
- Geometry of the Parabola: 2D (Geometric definition of the parabola, the reflection property, evidence that all parabolas are similar)
- Geometry of the Parabola: 3D (Proof that it is indeed a conic section)
- The Geometry of Conic Sections: 2D | 3D

- Unexpectedly related problems: minimizing certain sums of distances, and the locus of points from where a triangle...
- looks isosceles!
## Enrichment

- Symmetry
- Links to a wealth of K-12 materials
- The Two-Color Theorem
- A micro-unit that lays some groundwork for graph theory terminology in Discrete Math classes.

## Electives

After Algebra 2:

- Infinity
- Infinite sets, proof, chaos, fractals.
- Space
- Abstract algebra, symmetry, transformational geometry, dimension.
- Mathematics Overview
- A one-year review: some highlights of secondary school math.

## Teaching

Straightforward techniques for Reaching the Full Range of students in a heterogeneous class — in other words, any class.

Against Hyper-Acceleration: too many kids are accelerated in a counter-productive way.

The Assessment Trap: the wrong approach to assessment and the primacy of grades undermines student learning.

Taking Notes vs. Doing Math: Students cannot do both at the same time.

For a Tool-Rich Pedagogy: how manipulatives and technology can help transform the classroom.

Big-Picture Planning: mapping out a whole program, a course, a unit.

I analyzed the Common Core State Standards for high school math: Common Core, A Closer Look

Videos and links to articles about teaching, including a five-minute rant against time pressure.

## Manipulatives

## About

Brief video introduction, and links (virtual manipulatives, activities): Manipulatives

Links and curricular materials about algebra manipulatives: The Lab Gear

Curricular and enrichment links: Geometric Puzzles.

Debate on the appropriateness of using the geoboard to introduce the Pythagorean Theorem: an exchange with Don Chakerian.

Introduction to Base 10 blocks and the Lab Gear, followed by a general discussion of the uses and limitations of manipulatives: Manipulatives (in "Early Mathematics")

## Activities

- Physical, in-the-body lessons, spanning many topics in secondary school math:
- Kinesthetic Activities
Links to geoboard activities, most of which can also be carried out on dot paper.

- Links to pattern block activities:
- Angles (from
Geometry Labs)- Perimeter Patterns (in "Early Mathematics".)
- ...extended for teachers in Pattern Block Trains
- Big Dodecagon! — beautiful designs!
- Wallpaper Catalog — hands-on symmetry
Sample activities using the geoboard and the Lab Gear: Area (in "A New Algebra".)

- Sample activities using the CircleTrig geoboard (from
Geometry Labs):- Geometry: Angles
- Trigonometry: The Ten-Centimeter Circle
## Books

Activities that use a broad range of manipulatives:

Geometry Labs(free download)

Algebra Lab Gearbooks: free download | available from DidaxThree books of pentomino puzzles (free download!)

Working with Pentominoes, a book of lessons available from Didax

- Four books of geometric puzzles (free!), using superTangrams:
SuperTangram Activities, Books 1 and 2

SuperTangrams for Beginners, Books 1 and 2Information about a book (co-authored with George W. Hart) using the Zome System -- the ultimate 3D manipulative:

Zome Geometry

## Technology

Visual illustrations of various concepts, many suitable as writing prompts: Applets Directory

Electronic Graphing: many activities to deepen students' understanding of fundamental concepts (middle school to precalculus.)

Using the computer: Math: Visual and Interactive! (2013)

Programming: The Turtle in the Age of the Mouse (1997) | Boxer: A Teacher's Experience (2022).

## For Teachers

- Workshops, math program review, coaching
- Math Education Consulting

- Professional development for math teachers:
- Summer workshops

- Math lessons for math teachers
- Teachers' Mathematics