Unit 1: Scale Drawings
Lesson 2: Corresponding Parts and Scale Factors

This lesson develops the vocabulary for talking about scaling and scaled copies more precisely (MP6), and identifying the structures in common between two figures (MP7).

Specifically, students learn to use the term corresponding to refer to a pair of points, segments, or angles in two figures that are scaled copies. Students also begin to describe the numerical relationship between the corresponding lengths in two figures using a scale factor. They see that when two figures are scaled copies of one another, the same scale factor relates their corresponding lengths. They practice identifying scale factors.

A look at the angles of scaled copies also begins here. Students use tracing paper to trace and compare angles in an original figure and its copies. They observe that in scaled copies the measures of corresponding angles are equal.

Countdown Fractions in this Nrich game offers a motivating context in which to practice calculating with fractions. There is usually more than one way of hitting the target, which offers an opportunity for rich discussion on the merits of alternative methods.

This short video and interactive assessment activity is designed to teach first graders about counting rectangles, squares, and triangles in composite figures.

This short video and interactive assessment activity is designed to teach fourth graders about counting right angles in a turn.

This challenging problem and brainteaser gives first graders an opportunity to compose and decompose squares.

This short video and interactive assessment activity is designed to teach third graders about counting vertices and sides in various shapes.

This short video and interactive assessment activity is designed to teach fourth graders about counting the angles in a closed figure.

This short video and interactive assessment activity is designed to teach fifth graders about counting the number of perpendicular lines.

This Nrich interactive environment can be used with students, perhaps on an interactive whiteboard, for many different purposes. These might include, for example, exploring ideas associated with factors and multiples, or addition and subtraction. It is also an ideal context in which to investigate fractions and ratio, or to look at finding combinations.

This Nrich problem is intentionally difficult as it stands, but this allows us to focus on promoting resilience and perseverance with children.

The purpose of this curriculum guide is to provide OER lesson material and support activities for Pythagorean Theorem instruction. It is geared towards GED® requirements. Both printable and online options are provided.

The purpose of this curriculum guide is to provide OER lesson material and support activities for Pythagorean Theorem instruction. It is geared towards GED® requirements. Both printable and online options are provided.

Students are given a short video clip with a simple octagon. Can they predict where the arrow will be after a series of transformations?It might not be where you expect it.This great activity reinforces the ability of students to visualize geometric transformations in real-time, made predictions, analyze a bit of visual data, and the engagement tends to be through the roof!

This problem was designed to explore equivalence of change (ie. if a 10% decrease isn't the opposite of a 10% increase, what is? ) and to move students towards the concept: exponential growth and decay.

This short video and interactive assessment activity is designed to teach third graders about describing patterns using letters.

This short video and interactive assessment activity is designed to teach fourth graders about describing patterns using letters.

This lesson unit is intended to help teachers assess how well students are able to: Select appropriate mathematical methods to use for an unstructured problem; interpret a problem situation, identifying constraints and variables, and specify assumptions; work with 2- and 3-dimensional shapes to solve a problem involving capacity and surface area; and communicate their reasoning clearly.

Unit: Area and Surface Area
Lesson 19: Designing a Tent

In this culminating lesson, students use what they learned in this unit to design a tent and determine how much fabric is needed for the tent. The task prompts students to model a situation with the mathematics they know, make assumptions, and plan a path to solve a problem (MP4). It also allows students to choose tools strategically (MP5) and to make a logical argument to support their reasoning (MP3).

The lesson has two parts. In the first part, students learn about the task, gather information, and begin designing. The introduction is important to ensure all students understand the context. Then, after answering some preparatory questions in groups and as a class, students work individually to design and draw their tents. They use their knowledge of area and surface area to calculate and justify an estimate of the amount of fabric needed for their design.

The second part involves reflection and discussion of students’ work. Students explain their work to a partner or small group, discuss and compare their designs, and consider the impact of design decisions on the surface areas of their tents.

Depending on instructional choices made, this lesson could take one or more class meetings. The time estimates are intentionally left blank, as the time needed will vary based on instructional decisions made. It may depend on:

whether students use the provided information about tents and sleeping bags or research this information.
whether the Tent Design Planning Sheet is provided or students organize their work with more autonomy.
expectations around drafting, revising, and the final product.
how student work is ultimately shared with the class (not at all, informally, or with formal presentations).
Note: Students will need to bring in a personal collection of 10–50 small objects ahead of time for the first lesson of the next unit. Examples include rocks, seashells, trading cards, or coins.

This short video and interactive assessment activity is designed to teach third graders about determining unknown angles in parallelograms.