In this problem, students are given a picture of two triangles that appear to be similar, but whose similarity cannot be proven without further information. Asking students to provide a sequence of similarity transformations that maps one triangle to the other focuses them on the work of standard G-SRT.2, using the definition of similarity in terms of similarity transformations.

This short video and interactive assessment activity is designed to give fourth graders an overview of composite figures composed of squares and rectangles.

This short video and interactive assessment activity is designed to teach third graders about area in grid.

This short video and interactive assessment activity is designed to teach second graders an overview of area.

This short video and interactive assessment activity is designed to teach third graders an overview of area of squares and rectangles - word problems.

This short video and interactive assessment activity is designed to give fourth graders an overview of area and perimeter of rectangle.

This problem is part of a very rich tradition of problems looking to maximize the area enclosed by a shape with fixed perimeter. Only three shapes are considered here because the problem is difficult for more irregular shapes.

The purpose of this task is primarily assessment-oriented, asking students to demonstrate knowledge of how to determine the congruency of triangles.

Remember your multiplication tables? ... me neither. Brush up on your multiplication, division, and factoring skills with this exciting game. No calculators allowed! The students will be given mutiplication and division problems which they must answer. They also have the option of being given a number then stating the factors of how that number was attained using either multiplication or division.

Brush up on your multiplication, division, and factoring skills with this interactive multiplication chart. Three levels and timed or untimed options are available.

The CyberSquad tries to figure out a table arrangement for 20 workers in this video from Cyberchase.

In this video segment from Cyberchase, Matt tries for a second time to arrange tables and chairs to accommodate 20 workers.

Matt's third table arrangement helps fit all 20 workers at five tables in this video segment from Cyberchase.

This short video and interactive assessment activity is designed to teach fourth graders about arranging numbers in specific order (numbers to 1,000).

This short video and interactive assessment activity is designed to teach third graders about arranging numbers in specific orders.

This short video and interactive assessment activity is designed to teach fourth graders about arranging and ordering capacities (english units).

This this task about mixing paint requires students to graph ratios on a coordinate plane. It is a standard language in ratio problem.

This this task about mixing paint requires students to graph ratios on a coordinate plane. It is a standard language in ratio problem.

This activity is designed to determine the appropriate instructional level for a student in a one-on-one interaction with the teacher.

This activity is designed to determine the appropriate instructional level for a student in a one-on-one interaction with the teacher.