Featured Brain Teaser. Ask a friend to pick a number from 1 through 1,000. After asking him ten questions that can be answered yes or no, you tell him the number.

Data Analysis & Probability-Kindergarten. Practice; Counting & Cardinality; Algebraic Thinking; Number & Operations

In this unit, students use plastic as a context to explore mathematical and environmental concepts. The unit starts with an investigation of the surface area of a right cylinder, using a Geogebra applet to visualize and calculate the surface area of familiar plastic items.

Illuminations: Resources for Teaching Math. Contact Us; Join NCTM; Troubleshooting; About Illuminations; Lessons. All Lessons; Pre-K-2; 3-5; 6-8; 9-12; Brain Teasers

Investigating Functions with a Ferris Wheel: Distance vs. Width A Web Sketchpad activity helps students make sense of relationships between quantities, in this case the way that the distance a car travels around a Ferris wheel covaries with its "width" or horizontal distance from the center of the Ferris wheel

Who We Are. Illuminations is a project designed by the National Council of Teachers of Mathematics (NCTM).. What We Do. Illuminations works to serve you by increasing access to quality standards-based resources for teaching and learning mathematics, including interactive tools for students and instructional support for teachers.

Investigating Functions with a Ferris Wheel: Distance vs. Width A Web Sketchpad activity helps students make sense of relationships between quantities, in this case the way that the distance a car travels around a Ferris wheel covaries with its "width" or horizontal distance from the center of the Ferris wheel

Data Analysis & Probability-Kindergarten. Practice; Counting & Cardinality; Algebraic Thinking; Number & Operations

Students work with subtraction at the intuitive level as they explore number families and ways to decompose numbers to 10. They will also identify members of fact families. (A fact family is a set of three [or two] numbers that can be related by addition and subtraction, for example: 7 = 4 + 3, 7 = 3 + 4, 7 - 4 = 3, and 7 - 3 = 4.

This lesson plan presents a classic game-show scenario. A student picks one of three doors in the hopes of winning the prize. The host, who knows the door behind which the prize is hidden, opens one of the two remaining doors.