Whether it is for the unusual situation of schools being formally closed, a home school situation, or just students needing extra help, Phet simulators are quite informative. These math and science study aids are available online, and they can be accessed and used at no cost. They are ideal replacements for manipulatives when it is not possible to obtain manipulatives.
Not every student learns the same. Some can read and analyze a book and do fine. Others are visual learners, and must see, or even handle, something to understand a problem. This is a way to reach the visual learner, and even those who must interact with the problem.