Who is Salman Khan? That is the first question learners will answer after reading a New York Times article about the online math and science educator. They'll read the article and respond to eight questions that ask, who, what, when,...

At one time, humans, fueled by the animals and plants they ate and the wood they burned, or aided by their domesticated animals, provided most of the energy in use. All life operated within the fairly immediate flow of energy from the...

What kind of evidence could demonstrate that humans have begun to dominate and alter the life systems of Earth and have entered a new geological epoch? This article discusses the suggestion that we have entered the Anthropocene and...

The quest for energy has always been a balancing act. As humans have gained greater control over their environment, they've found abundant resources - and faced numerous challenges. This article traces the history of our quest for energy.

Spanning three centuries of history, from the dawn of the industrial age to modern times, three diverse thinkers developed their own landmark theories on commerce, labor, and the global economy. The three economists profiled in this...

This resource from Khan Academy provides foundational-level practice questions over the expansion of presidential power. These questions are intended for students taking high school or college level American Government and Civics...

This resource from Khan Academy provides practice questions over The Articles of Confederation. These questions are intended for students taking high school or college level American Government and Civics courses, including the AP...

This study resource from Khan Academy provides the full text of The Articles of Confederation. These questions are intended for students taking high school or college level American Government and Civics courses, including the AP...

This resource from Khan Academy provides a study resource about the weaknesses of the Articles of Confederation, Shay's Rebellion, and the needed call for a new Constitution. These questions are intended for students taking high school...

Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Find the slopes of lines whose equations are given in various forms. For example, find the slope of 2x+3y=5. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

In this exercise, students practice addition word problems within 10. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

In this exercise, students practice subtraction word problems within 10. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

Practice solving word problems by adding small numbers (numbers 10 or less). Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Practice solving word problems by subtracting small numbers (numbers 10 or less). Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Find the distance between points, graph points, and interpret data on coordinate planes to solve word problems. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Practice computing the areas of rectangles that have fractional side lengths. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Sal arranges digits to make the largest or smallest possible number. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Solve quadratic equations of the form ax^2+bx+c by completing the square. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or receive hints.

Find a linear function that represents a real-world relationship that is given verbally. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or receive hints.

In this exercise, students practice decomposing fractions with denominators of 100. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

Find the determinant of a given 2x2 matrix. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Solve equations where the unknown is a matrix, by using matrix addition and subtraction. Students receive immediate feedback and have the opportunity to try questions repeatedly or receive hints.

Find specific elements (also called entries) of given matrices. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.