Use the Floats and Anchors context as well as physical and digital materials to help students understand integer addition and subtraction.

# Browse

## Construct It! Introducing Integers with Floats and Anchors

### Christy Pettis and Aran Glancy

## Beware of “Gaps” in Students’ Fraction Conceptions

### Patrick L. Sullivan, Joann E. Barnett, and Kurt Killion

Many students have a dominant part-whole conception of fractions. We examine why this is problematic and explore strategies to move students beyond this limitation.

## Building Algebraic Procedures From Concepts: Like Terms

### Leah M. Frazee and Adam R. Scharfenberger

This task sequence for adding and subtracting like terms—grounded in the concepts of equivalence and algebra as generalized arithmetic—helps students see connections between concepts and procedures in algebra.

## Digital Learning Routes: An Example of Mathematical Modeling

### Salomé Martínez, Flavio Guiñez, and Darío González

An online activity provides instructional strategies that can help students engage in mathematical modeling and autonomous learning.

## Broken Ceiling Lights: Circular Area Without the Radius

### Nicholas J. Gilbertson

A customer walks in to a lighting store with a broken ceiling light, and the solution to finding a replacement glass illuminates an alternative approach to finding the circumference and area of a circle without knowing the circle’s center, radius, or diameter.

## Exploring Young Children’s Math Thinking in Sandcastle Building

### Hannah Tan and Cynthia Lim

Children explore concepts of capacity and height measurement through sand play in nursery class.

## Problems to Ponder

### Chris Harrow and Justin Johns

Problems to Ponder provides 28 varying, classroom-ready mathematics problems that collectively span PK–12, arranged in the order of the grade level. Answers to the problems are available online. Individuals are encouraged to submit a problem or a collection of problems directly to mtlt@nctm.org. If published, the authors of problems will be acknowledged.

## Using Public Records to Scaffold Joint Sense Making

### Keith R. Leatham, Blake E. Peterson, Ben Freeburn, Sini W. Graff, Laura R. Van Zoest, Shari L. Stockero, and Nitchada Kamlue

Teachers can more productively use board work to scaffold joint sense making.

## Construct It! Progressively Precise: Three Levels of Geometric Constructions

### Carmen Petrick Smith

This article shares an activity scaffolding the construction of the circumcenter of a triangle, culminating with a Triangle-Ball Championship game.

## Construct It! Triangle Puzzle Challenges

### Enrique Ortiz

This article presents an original puzzle that supports students’ development of visual thinking and geometry ideas based on the Van Hiele levels of geometric thought.