Students quantify the percent of light reflected from solutions containing varying concentrations of red dye using LEGO© MINDSTORMS© NXT bricks and light sensors. They begin by analyzing a set of standard solutions with known concentrations of food coloring, and plot data to graphically determine the relationship between percent reflected light and dye concentration. Then they identify dye concentrations for two unknown solution samples based on how much light they reflect. Students gain an understanding of light scattering applications and how to determine properties of unknown samples based on a set of standard samples.

This video lesson examines the meaning of the equal sign as we work to solve unknowns in multiplication and division equations.

This resource is from Tools4NCTeachers.The goals of this lesson are to a) use objects or drawings to find the number that makes 10 when added to a known number, and b) record answers using drawings or expressions.Remix this lesson to share addtional problems, extension ideas, or student work samples.

This resource is part of Tools4NCTeachers.

This file contains a set of 17 problem solving tasks around decomposing numbers within 10 (where both addends are unknown). Each of the tasks has its own recording sheet, which may be copied for the students. Page 1 contains a general scoring rubric, and page 2 contains sample student work.

We'd love to see your student work samples! Please consider remixing this task to include work samples.

This resource is part of Tools4NCTeachers.

Students are asked to solve an unknown addend, show their work using pictures, numbers or words, and record a matching equation. A scoring rubric is included. The task may be used for instructional or assessment purposes.

This lesson is part of Tools4NCTeachers.In this lesson, students practice solving unknown-addend problems by using addition strategies or changing to subtraction problems. Task cards and extension actvities are included. 

This resource is from Tools4NCTeachers.  This is a set of nine (9) tasks, which may be used for instruction or assessment. Each attachment contains a separate task, rubric, and student recording sheet. The word problems in these tasks involve 'adding to' or 'taking from' a quantity. In these specific problems, the change is unknown. For example:There were 17 ducks in the pond.  Some flew away, and now there are 8 ducks in the pond.  How many ducks flew away?Remix this resource to include student work samples or addtional tasks.

This resource is from Tools4NCTeachers.  This task may be used for instruction or assessment.  It focuses around a put-together/take apart problem where one of the addends is unknown.  The file contains the task, rubric, and student recording sheet. Remix this resource to include student work samples or addtional tasks.

This resource is from Tools4NCTeachers.In this lesson, students explore making and breaking cube trains.  Based on the part of the cube train that is shown, the group races to guess the hidden part to develop the concepts of adding and subtracting within 20. 

This resource is from Tools4NCTeachers. This file contains a set of 4 tasks (including scoring rubric and student recording sheet).  The tasks may be used for instruction or assessment.  Each focuses on solving a problem with an unknown addend.  Remix this resource to include student work samples or addtional tasks.

This resource is from Tools4NCTeachers.In this lesson, students use their understanding of word problems to sort problems based on type.  The focus for students in this lesson shifts from solving word problems to analyzing word problem structures in order to group like problems.  The purpose is to help students understand and visualize problems so they will know how to write equations that match and know what operation is needed to solve.  This lesson focuses on sorting addition and subtraction word problems with a specific focus on Take Apart and Put Together types.  The lesson, however, can be adjusted to use with any problem types you notice students need more experience with.  You could also adjust the number size in the problems to use this lesson at different times in the year. 

This resource is part of Tools4NCTeachers.

In this lesson, students use their understanding of word problems to sort problems based on type. The focus for students in this lesson shifts from solving word problems to analyzing word problem structures in order to group like problems. The purpose is to help students understand and visualize problems so they will know how to write equations that match and know what operation is needed to solve. This lesson focuses on sorting addition and subtraction word problems with a specific focus on Take Apart and Put Together types. The lesson, however, can be adjusted to use with any problem types you notice students need more experience with. You could also adjust the number size in the problems to use this lesson at different times in the year.

This resource is part of Tools4NCTeachers.

In this lesson, students solve a word problem using a strategy of choice and share the strategy to develop the concept of representing and solving problems involving addition and subtraction within 20. This lesson format may be used with any problem type appropriate for the grade.

This resource is part of Tools4NCTeachers.

In this task, students are faced with a both addends unknown problem. They must find as many solutions as possible using pictures, numbers or words. A scoring rubric is included. The task may be used for instructional or assessment purposes.

This resource is from Tools4NCTeachers.In this lesson, students explore the commutative and associative properties of addition as they solve word problems with multiple solutions.  This lesson will help students learn to represent and solve problems with equations that have three addends. This file contains answer keys, student recording pages, and extension problems.