# Browse

## You are looking at 1 - 10 of 168 items for :

• Reasoning/Sense Making/Proof
• Refine by Access: All content
Clear All
Restricted access

## Broken Ceiling Lights: Circular Area Without the Radius

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.

Restricted access

## Problems to Ponder

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.

Restricted access

## Using Public Records to Scaffold Joint Sense Making

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

Restricted access

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

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

Restricted access

## Prove It! Graph Theory and Induction: The Next Big Thing

Eighth-grade students participated in a two-day lab exploring graph theory. In addition to learning about a completely new topic, they experienced a subtle introduction to proof by induction.

Restricted access

## Let’s Be Flexible

Restricted access

## Problems to Ponder

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.

Restricted access

Support students in conjecturing in ways that can promote their agency in the learning process.

Restricted access

## GPS: Teaching Shapes Inclusively

Growing Problem Solvers provides four original, related, classroom-ready mathematical tasks, one for each grade band. Together, these tasks illustrate the trajectory of learners’ growth as problem solvers across their years of school mathematics.

Restricted access

## Making Sense of Algebraic Expressions in Context

Explore three challenges that students faced and how they made progress.