This video module presents an introduction to cryptography - the method of sending messages in such a way that only the intended recipients can understand them. In this very interactive lesson, students will build three different devices for cryptography and will learn how to encrypt and decrypt messages. There are no prerequisites for this lesson, and it has intentionally been designed in a way that can be adapted to many audiences. It is fully appropriate in a high school level math or computer science class where the teacher can use it to motivate probability/statistics or programming exercises. nteractive lesson, students will learn to build the cryptography devices and will learn how to send and ''crack'' secret messages.

This Nrich activity challenges students to translate oral directions into actions to build a pattern with blocks.

This lesson integrates language arts, music, and math. The children will listen to the story "Count on Bunnies". They will be given the opportunity to act out the story and solve bunny equations. After listening to the song "Five Young Rabbits," the children will take turns being rabbits and pantomiming the actions as the class sings. The children will combine the rabbits at the end of each verse to see how many rabbits have been added. Then they will work in pairs to create their own rabbit equations.

Unit 3: Unit Rates and Percentages
Lesson 1: The Burj Khalifa

In the previous unit, students began to develop an understanding of ratios and familiarity with ratio and rate language. They represented equivalent ratios using discrete diagrams, double number lines, and tables. They learned that a:b is equivalent to every other ratio sa:sb, where s is a positive number. They learned that “at this rate” or “at the same rate” signals a situation that is characterized by equivalent ratios.

In this unit, students find the two values a/b and b/a that are associated with the ratio a:b, and interpret these values as rates per 1. For example, if a person walks 13 meters in 10 seconds, that means they walked 13/10 meters per 1 second and 10/13 seconds per 1 meter.

To kick off this work, in this lesson, students tackle a meaty problem that rewards finding and making sense of a rate per 1 (MP1). Note there is no need to use or define the term “rate per 1” with students in this lesson. All of the work and discussion takes place within a context, so students will be expected to understand and talk about, for example, the minutes per window or the meters climbed per minute, but they will not be expected to use or understand the more general term “rate per 1.”

This is an integrated lesson which is introduced using the book "The Very Hungry Caterpillar" by Eric Carle. Butterfly metamorphosis is explored through art, math, and writing.

In this Nrich activity students will look for patterns and options in a common everyday situation.

This Nrich problem gives children the chance to identify and continue number patterns, counting on and back in ones and twos. It is also a good chance for learners to understand the benefits of a trial and improvement approach.

This Geometry Concept Collection is a rigorous presentation of high school geometry. It is fully correlated with the Common Core State Standards.

This Turtle Diary game helps students practice addition through solving addition problems through a car racing game. This game is a great option for independent center practice, whole group instruction, or small group instruction

In this Nrich activity students explore patterns with numbers in a square. This activity encourages multiple responses, creativity, discourse, and number sense.

This Nrich problem can be used to introduce learning about percentage increases and decreases.

Code-breaking is often about partial conclusions gradually adding up to possibilities. This problem is unlikely to be done instantly by most students, so discussion should bring up lots of helpful thoughts to share around a group, energizing explanation and stimulating individuals into new reasoning and strategy.

This video explains how cicadas emerge every 13 or 17 years, which are prime numbers.

Students apply and interpret their understanding of area in a real world situation.

In this Nrich problem students build on their existing knowledge of proportions to build a function in an engaging context.

An interactive applet and associated web page that demonstrate the circumference of a circle. The applet shows a circle with a radius line. The radius endpoints are draggable and the circle is resized accordingly. The formula relating radius to circumference is updated continually as you drag. Introduces the idea of Pi. The formula can be hidden for class discussion and estimation. See also the entries for circumference and diameter. See also entries for radius and diameter. 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.

Two blobs of clay go on an enjoyable adventure as they transform themselves into fun shapes and new things throughout their escapade. What will they be by the end of the book? The resource includes a lesson plan/book card, a design challenge, and copy of a design thinking journal that provide guidance on using the book to inspire students' curiosity for design thinking. Maker Challenge: Design a stop-motion video that morphs an item of your choice into another item. Before you begin, sketch out the process you’ll take to transform your item.

A document is included in the resources folder that lists the complete standards-alignment for this book activity.

In this online game, Coin Bubble by Greg Tang Math, students make a given monetary figure using a ten frame of coins. Students work with higher value denominations as the game progresses. In addition, students can use exchanges to get to their figure faster.

Unit 2: Introducing Ratios
Lesson 4: Color Mixtures

This is the second of two lessons that help students make sense of equivalent ratios through physical experiences. In this lesson, students mix different numbers of batches of a recipe for green water by combining blue and yellow water (created ahead of time with food coloring) to see if they produce the same shade of green. They also change the ratio of blue and yellow water to see if it changes the result. The activities here reinforce the idea that scaling a recipe up (or down) requires scaling the amount of each ingredient by the same factor (MP7). Students continue to use discrete diagrams as a tool to represent a situation.

For students who do not see color, the lesson can be adapted by having students make batches of dough with flour and water. 1 cup of flour to 5 tablespoons of water makes a very stiff dough, and 1 cup of flour to 6 tablespoons of water makes a soft (but not sticky) dough. In this case, doubling a recipe yields dough with the same tactile properties, just as doubling a colored-water recipe yields a mixture with the same color. The invariant property is stiffness rather than color. The principle that equivalent ratios yield products that are identical in some important way applies to both types of experiments.

Unit 7: Rational Numbers
Lesson 16: Common Factors

In this lesson, students use contextual situations to learn about common factors and the greatest common factor of two whole numbers. They develop strategies for finding common multiples and least common multiples. They develop a definition of the terms common factor and greatest common factor for two whole numbers (MP6).