# Guess My Number

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This problem asks the students to represent a sequence of operations using an expression and then to write and solve simple equations. The problem is posed as a game and allows the students to visualize mathematical operations. It would make sense to actually play a similar game in pairs first and then ask the students to record the operations to figure out each other's numbers.

Material Type: Activity/Lab

Author: Illustrative Mathematics

# Weed killer

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The principal purpose of the task is to explore a real-world application problem with algebra, working with units and maintaining reasonable levels of accuracy throughout.

Material Type: Activity/Lab

Author: Illustrative Mathematics

# Profit of a company

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This task compares the usefulness of different forms of a quadratic expression. Students have to choose which form most easily provides information about the maximum value, the zeros and the vertical intercept of a quadratic expression in the context of a real world situation. Rather than just manipulating one form into the other, students can make sense out of the structure of the expressions.

Material Type: Activity/Lab

Author: Illustrative Mathematics

# CTE Health Sciences: False Positives

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This task was developed by high school and postsecondary mathematics and health sciences educators, and validated by content experts in the Common Core State Standards in mathematics and the National Career Clusters Knowledge & Skills Statements. It was developed with the purpose of demonstrating how the Common Core and CTE Knowledge & Skills Statements can be integrated into classroom learning - and to provide classroom teachers with a truly authentic task for either mathematics or CTE courses.

Material Type: Activity/Lab, Lesson Plan

# CTE Health Sciences: Medication Dosage

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This task was developed by high school and postsecondary mathematics and health sciences educators, and validated by content experts in the Common Core State Standards in mathematics and the National Career Clusters Knowledge & Skills Statements. It was developed with the purpose of demonstrating how the Common Core and CTE Knowledge & Skills Statements can be integrated into classroom learning - and to provide classroom teachers with a truly authentic task for either mathematics or CTE courses.

Material Type: Activity/Lab, Lesson Plan

# Chocolate Bar Sales

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In this task students use different representations to analyze the relationship between two quantities and to solve a real world problem. The situation presented provides a good opportunity to make connections between the information provided by tables, graphs and equations.

Material Type: Activity/Lab

Author: Illustrative Mathematics

# Solving Linear Equations in One Variable

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This lesson unit is intended to help teachers assess how well students are able to: solve linear equations in one variable with rational number coefficients; collect like terms; expand expressions using the distributive property; and categorize linear equations in one variable as having one, none, or infinitely many solutions. It also aims to encourage discussion on some common misconceptions about algebra.

Material Type: Assessment, Lesson Plan

# Steps to Solving Equations

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This lesson unit is intended to help teachers assess how well students are able to: form and solve linear equations involving factorizing and using the distributive law. In particular, this unit aims to help teachers identify and assist students who have difficulties in: using variables to represent quantities in a real-world or mathematical problem and solving word problems leading to equations of the form px + q = r and p(x + q) = r.

Material Type: Assessment, Lesson Plan

# Proofs of the Pythagorean Theorem

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This lesson unit is intended to help teachers assess how well students are able to produce and evaluate geometrical proofs. In particular, this unit is intended to help you identify and assist students who have difficulties in: interpreting diagrams; identifying mathematical knowledge relevant to an argument; linking visual and algebraic representations; and producing and evaluating mathematical arguments.

Material Type: Assessment, Lesson Plan

# Hexagon

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A web page and interactive applet illustrating the properties of a hexagon (6 sided polygon). The applet shows a hexagon where the user can drag any vertex to reshape it. User can see that the interior and exterior angles are constant in a regular hexagon, but vary in an irregular version. Controls allow the display or hiding of the diagonals, and triangles within the hexagon. The web page lists the properties of a hexagon including interior angles, exterior angles, sum of exterior angles, area, number of diagonals and number of internal triangles. Links to pages with generalized properties of all polygons. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

Author: John Page

# Finding Equations of Parallel and Perpendicular Lines

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This lesson unit is intended to help teachers assess how well students are able to understand the relationship between the slopes of parallel and perpendicular lines and, in particular, to help identify students who find it difficult to: find, from their equations, lines that are parallel and perpendicular; and identify and use intercepts. It also aims to encourage discussion on some common misconceptions about equations of lines.

Material Type: Assessment, Lesson Plan

# Dilating a Line

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This task gives students the opportunity to verify that a dilation takes a line that does not pass through the center to a line parallel to the original line, and to verify that a dilation of a line segment (whether it passes through the center or not) is longer or shorter by the scale factor.

Material Type: Activity/Lab

Author: Illustrative Mathematics

# Find the Missing Angle

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This task "Uses facts about supplementary, complementary, vertical, and adjacent angles in a multi-step problem to write and solve simple equations for an unknown angle in a figure (7.G.5)" except that it requires students to know, in addition, something about parallel lines, which students will not see until 8th grade.

Material Type: Activity/Lab

Author: Illustrative Mathematics

Remix

# OER Fellowship Project: City planning with parallel lines

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This project introduces students to parallel lines and angles through videos, practice exercises, simulations, hands-on activities, and student presentations.

Material Type: Activity/Lab, Simulation

Author: Megan Simmons

# Identifying Similar Triangles

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This lesson unit is intended to help you assess how students reason about geometry and, in particular, how well they are able to: use facts about the angle sum and exterior angles of triangles to calculate missing angles; apply angle theorems to parallel lines cut by a transversal; interpret geometrical diagrams using mathematical properties to identify similarity of triangles.

Material Type: Assessment, Lesson Plan

# When Does SSA Work to Determine Triangle Congruence?

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The triangle congruence criteria, SSS, SAS, ASA, all require three pieces of information. It is interesting, however, that not all three pieces of information about sides and angles are sufficient to determine a triangle up to congruence. In this problem, we considered SSA. Also insufficient is AAA, which determines a triangle up to similarity. Unlike SSA, AAS is sufficient because two pairs of congruent angles force the third pair of angles to also be congruent.

Material Type: Activity/Lab

Author: Illustrative Mathematics