4th grade Common Core State Standards skill. Becoming familiar with common fractions and decimals and converting between them. Practice this yourself on Khan Academy right now: https://www.khanacademy.org/math/cc-fourth-grade-math/cc-4th-decimals/cc-4th-common-fractions-decimals/e/common-fractions-and-decimals Watch the next lesson: https://www.khanacademy.org/math/cc-fourth-grade-math/cc-4th-decimals/cc-4th-common-fractions-decimals/v/common-fractions-halves-math-4th-grade-khan-academy Missed the previous lesson? https://www.khanacademy.org/math/cc-fourth-grade-math/cc-4th-decimals/cc-4th-decimals-to-fractions/v/converting-decimals-to-fractions-1-ex-3 4th grade math on Khan Academy: 4th grade is the time to start really fine-tuning your arithmetic skills. Not only will you be a multi-digit addition and subtraction rockstar, but you'll extend the multiplication and division that you started in 3rd grade to several digits. You'll also discover that you sometimes have something left over (called a "remainder") when you divide. In 3rd grade you learned what a fraction is. Now you'll start adding, subtracting, multiplying, and comparing them. You'll also see how they relate to decimals. On other fronts, you'll learn how to convert between different units (which is super important when comparing the size and speed of robot unicorns in different countries) and continue your journey thinking about various shapes in two dimensions. Some of the foundational concepts of geometry (like lines, rays and angles) also get introduced. As always, we'll round this out with a healthy dose of applied word problems and explorations of number patterns and properties (including the ideas of factors, multiples and prime numbers). The fun must not stop! (Content was selected for this grade level based on a typical curriculum in the United States.) ... https://www.youtube.com/watch?v=lh2mp0aqSh8 Note: All Khan Academy content is available for free at (www.khanacademy.org)

Using an integrating factor to make a differential equation exact Watch the next lesson: https://www.khanacademy.org/math/differential-equations/first-order-differential-equations/exact-equations/v/integrating-factors-2?utm_source=YT&utm_medium=Desc&utm_campaign=DifferentialEquations Missed the previous lesson? https://www.khanacademy.org/math/differential-equations/first-order-differential-equations/exact-equations/v/exact-equations-example-3?utm_source=YT&utm_medium=Desc&utm_campaign=DifferentialEquations Differential Equations on Khan Academy: Differential equations, separable equations, exact equations, integrating factors, homogeneous equations. About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content. ... https://www.youtube.com/watch?v=j511hg7Hlbg Note: All Khan Academy content is available for free at (www.khanacademy.org)