This task asks students to use two different denominators to subtract fractions. The purpose of this is to help students realize that any common denominator will work, not just the least common denominator.

In this task students have the opportunity to construct linear and exponential functions, including arithmetic and geometric sequences, given a graph, a description of a relationship, or two input-output pairs (include reading these from a table).

This real world problem is appropriate for mental mathematics and students should be encouraged to think through the solution mentally.

The purpose of this task is to give 4th grade students a problem involving an unknown quantity that has a clear visual representation. Students must understand that the four interior angles of a rectangle are all right angles and that right angles have a measure of 90_ and that angle measure is additive.

This tasks examines how to calculate the area of an equilateral triangle using high school geometry.

This task helps students solidify their understanding of linear functions and push them to be more fluent in their reasoning about slope and y-intercepts. This task has also produced a reasonable starting place for discussing point-slope form of a linear equation.

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.

This task asks students to solve addition and subtraction equations with different structures so that they are able to see the connections between addition and subtraction more easily.

In this task students are asked to write an equation to solve a real-world problem. There are two natural approaches to this task. In the first approach, students have to notice that even though there is one variable, namely the number of firefighters, it is used in two different places. In the other approach, students can find the total cost per firefighter and then write the equation.

This task is the first in a series of three tasks that use inequalities in the same context at increasing complexity in 6th grade, 7th grade and in HS algebra. Students write and solve inequalities, and represent the solutions graphically.

This task is the second in a series of three tasks that use inequalities in the same context at increasing complexity in 6th grade, 7th grade and in HS algebra. Students write and solve inequalities, and represent the solutions graphically.

This task is the last in a series of three tasks that use inequalities in the same context at increasing complexity in 6th grade, 7th grade and in HS algebra. Students write and solve inequalities, and represent the solutions graphically. The progression of the content standards is 6.EE.8 to 7.EE.4 to A-REI.12.

This game will reinforce number before and after as well as reading and sequencing numbers.

This task can be used to both assess student understanding of systems of linear equations or to promote discussion and student thinking that would allow for a stronger solidification of these concepts.

To become familiar with the transfer of energy in the form of quantum, students perform flame tests, which is one way chemical engineers identify elements by observing the color emitted when placed in a flame. After calculating and then preparing specific molarity solutions of strontium chloride, copper II chloride and potassium chloride (good practice!), students observe the distinct colors each solution produces when placed in a flame, determine the visible light wavelength, and apply that data to identify the metal in a mystery solution. They also calculate the frequency of energy for the solutions.

Students discover fluid dynamics related to buoyancy through experimentation and optional photography. Using one set of fluids, they make light fluids rise through denser fluids. Using another set, they make dense fluids sink through a lighter fluid. In both cases, they see and record beautiful fluid motion. Activities are also suitable as class demonstrations. The natural beauty of fluid flow opens the door to seeing the beauty of physics in general.

Students explore the impact of changing river volumes and different floodplain terrain in experimental trials with table top-sized riverbed models. The models are made using modeling clay in aluminum baking pans placed on a slight incline. Water added "upstream" at different flow rates and to different riverbed configurations simulates different potential flood conditions. Students study flood dynamics as they modify the riverbed with blockages or levees to simulate real-world scenarios.

The purpose of this task is for students to translate between measurements given in a scale drawing and the corresponding measurements of the object represented by the scale drawing.