Lesson: Introduces students to modular (clock) arithmetic and how modular arithmetic can be used to encode messages using simple shift, multiple and affine ciphers.

Lesson: Introduces students to fractions and explores basic mathematical operations with fractions, comparing fractions, and converting fractions into decimals or percents.

Lesson: Introduces students to fractions and explores basic mathematical operations with fractions, comparing fractions, and converting fractions into decimals or percents.

Lesson: Students practice arithmetic skills. Can be tailored for practice of all types of single operation arithmetic ranging from simple addition to operations with integers and decimals.

Activity: Students run a simulation of how a fire will spread through a stand of trees, learning about probability and chaos. Parameters: Forest density, wind direction, size of forest.

Activity: Students work step-by-step through the generation of a different Hilbert-like Curve (a fractal made from deforming a line by bending it), allowing them to explore number patterns in sequences and geometric properties of fractals.

Activity: Students play a generalized version of connect four, gaining the chance to place a piece on the board by answering arithmetic questions (addition, subtraction, multiplication, division). Parameters: time, difficulty level, types of questions. Arithmetic Four is one of the Interactivate assessment games.

Activity: Arithmetic Quiz gives the user randomized questions to answer on arithmetic with whole numbers and integers. Parameters: Level of difficulty and types of questions. Arithmetic Quiz is one of the Interactivate assessment quizzes.

Activity: The same as "Bounded Fraction Pointer" but there is no arrow to help the user determine the value of a fraction between the two endpoints. Bounded Fraction Finder is one of the Interactivate assessment explorers.

Activity: Determine the value of two fractions you have chosen (which are represented as points on a number line). Then find a fraction whose value is between your two fractions (using an arrow on the number line as a guide) and determine its value. Bounded Fraction Pointer is one of the Interactivate assessment explorers.

Activity: Learn about fractions between 0 and 1 by repeatedly deleting portions of a line segment, and also learn about properties of fractal objects. Parameter: fraction of the segment to be deleted each time.

Activity: Run a simulation of how a fire will spread through a stand of trees, learning about probability and chaos. Parameters: Probability that a tree will set fire to each of its eight neighbors.

Activity: Visually represent two unique fractions that are equivalent to a given fraction. The fractional value is shown on a number line after you check to see if your fraction is correct. Equivalent Fraction Finder is one of the Interactivate assessment explorers.

Activity: Visually represent two unique fractions that are equivalent to a given fraction. The fractional value is shown on a number line as you color in the fraction. Equivalent Fraction Pointer is one of the Interactivate assessment explorers.

Activity: Run a simulation of how a fire will spread through a stand of trees, learning about probability and chaos. Parameters: Probability that a tree catches fire if its neighbor is on fire.

Activity: Determine the value of two given fractions represented as points on a number line. Then find a fraction whose value is between the two given fractions and determine its value. Fraction Finder is one of the Interactivate assessment explorers.

Activity: Students play a generalized version of connect four, gaining the chance to place a piece after simplifying fractions, converting fractions to decimals and percentages, and answering algebra questions involving fractions. Choose difficulty level, question types, and time. Fraction Four is one of the Interactivate assessment games.

Activity: Determine the value of two given fractions represented as points on a number line. Then find a fraction whose value is between the two given fractions (using an arrow on the number line as a guide) and determine its value. Fraction Pointer is one of the Interactivate assessment explorers.

Activity: Test your fraction skills by answering questions. This quiz asks you to simplify fractions, convert fractions to decimals and percentages, and answer algebra questions involving fractions. Choose difficulty level, question types, and time. Fraction Quiz is one of the Interactivate assessment quizzes.

Activity: Visualize fractions by coloring in the appropriate portions of either a circle or a square, then order those fractions from least to greatest. Fraction Sorter is one of the Interactivate assessment explorers.

Activity: Step through the generation of a Hilbert Curve -- a fractal made from deforming a line by bending it, and explore number patterns in sequences and geometric properties of fractals.

Activity: Step through the generation of the Koch Snowflake -- a fractal made from deforming the sides of a triangle, and explore number patterns in sequences and geometric properties of fractals.

Activity: Mixtures allows exploration of percents through two piles of colored and uncolored chips. The user must decide how many chips to color to create the desired percentage of colored chips compared to the total pile. Mixtures is one of the Interactivate assessment explorers.

Activity: Students play a generalized version of connect four, gaining the chance to place a piece on the board by answering order of operations questions (addition/subtraction, multiplication/division, exponents, and parentheses). Parameters: time, difficulty level, types of questions. Order of Operations Four is one of the Interactivate assessment games.

Activity: This activity allows the user to practice order of operations with addition/subtraction, multiplication/division, exponents, and parentheses. Order of Operations Quiz is one of the Interactivate assessment quizzes.

Activity: Learn about number patterns in sequences and recursions by specifying a starting number, multiplier, and add-on. The numbers in the sequence are displayed on a graph, and they are also listed below the graph.

Activity: Step through the generation of Sierpinski's Carpet -- a fractal made from subdividing a square into nine smaller squares and cutting the middle one out. Explore number patterns in sequences and geometric properties of fractals.

Activity: Step through the generation of Sierpinski's Triangle -- a fractal made from subdividing a triangle into four smaller triangles and cutting the middle one out. Explore number patterns in sequences and geometric properties of fractals.

Activity: Determine the value of a given fraction represented as a point on a number line. Then find a fraction whose value is a given fraction. Fraction Pointer is one of the Interactivate assessment explorers.

Activity: Step through the tortoise and hare race, based on Zeno's paradox, to learn about the multiplication of fractions and about convergence of an infinite sequence of numbers.