Throughout their lives, Barbara and Morton Mandel have acquired examples by Modern and Post War masters – from Pablo Picasso to Donald Judd. Watch below as they recount their journey as passionate collectors of 20th and 21st-century art. | Sotheby's

82K views · 1K reactions | This Quartic Polynomial Equation Turned Out to Be a Pair of Nice Quadratic Equations With Four Real Roots Here Is Our Thinking Process As We Solve This Ukrainian Math Problem Solving math problems is not a clean, linear path we oftentimes see when we watch math videos. Behind the scenes, there are a lot of trials and errors, detours, failed approaches, or even mental blocks. | Math Avenue : Learn Math By Examples | Facebook

6.6M views · 6.1K reactions | Did you know opossums have superpowers?...