Sal demonstrates adding and subtracting rational expressions with like denominators. [3:44]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Demonstrates how to use a number line to visualize and solve addition and subtraction word problems. [4:27]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

To add the vectors (x₁,y₁) and (x₂,y₂), we add the corresponding components from each vector: (x₁+x₂,y₁+y₂). Here's a concrete example: the sum of (2,4) and (1,5) is (2+1,4+5), which is (3,9). There's also a nice graphical way to add vectors, and the two ways will always result in the same vector.​​

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Demonstrates how to add 35 to 27 using drawings of base ten cubes to represent 1s and 10s. [4:36]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Video tutorial demonstrates how to solve an addition word problem with numbers less than 100. [3:30]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Learn how to solve addition and subtraction word problems using gorillas and cookies as examples. [5:31]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Given a 2-digit addition or subtraction problem, video demonstrates how to decide which number line matches up with it. [1:56]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

All art is political in the sense that all art takes place in the public arena and engages with an already existing ideology. Chinese artist, Ai Weiwei, offers an important contemporary example. The news that Chinese artist Ai Weiwei has been detained by authorities has prompted significant concern. Ai Weiwei has ben arrested by the Chinese authorities.

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

In this art history video discussion Beth Harris and Steven Zucker look at Albrecht Durer's "Self-Portrait, 1500." (Alte Pinakothek, Munich).

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Aldol and retro-aldol are two important classes of chemical reactions, occasionally encountered in biochemistry too.

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This art history video examines the "Alexander Mosaic" c. 100 B.C.E., tessera mosaic from the House of the Faun, Pompeii. This Roman floor mosaic may be based on a lost Hellenistic painting by Philoxenos of Eretria, The Battle of Issus, c. 315 B.C.E.). Museo Archeologico Nazionale, Naples.

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

This site teaches Arithmetic with Polynomials and Rational Expressions to High Schoolers through a series of 4333 questions and interactive activities aligned to 26 Common Core mathematics skills.

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This site teaches High Schoolers how to create equations through a series of 298 questions and interactive activities aligned to 5 Common Core mathematics skills.

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Video solving for the domain and range of a specific function defined verbally. Equation for function is found before defining the domain and range. [3:36]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Video solving a radical equation that results in a quadratic equation and yields an extraneous solution. Explains how the extraneous solution appeared. [11:10]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

A step-by-step demonstration on how to solve a rational equation and eliminate any extraneous solutions. [3:03]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

This video demonstrates how to graph a linear equation by creating a table of x, y values to use as coordinates for the graph of the line. The second example demonstrates how to take a word problem and create a table of values to graph in order to show the linear relationship applied in the problem. The last sample problem shows how to interpret a linear graph in order to determine specified values. [13:09]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

In this example, Sal finds the input value for which f(t)=13, given that f(t)=-2t+5. [1:39]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Sal considers two cases of polynomial identities and their proofs. [7:38]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Sal divides a rational expression using long division. [3:24]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.