You can share your screen in Panopto or Zoom live or recorded. There are many drawing programs available to you depending on the type of device you are using. A Microsoft Surface or other Tablet type computers are ideal because you can use a stylus to write rather than a mouse.
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MS Office Ink is fully integrated with all MS Office apps: https://support.office.com/en-us/article/draw-and-write-with-ink-in-office-6d76c674-7f4b-414d-b67f-b3ffef6ccf53
EquatIO
EquatIO is a math extension that allows you to insert, edit, and interact with digital math in the G Suite Environment or with Microsoft word.
https://support.texthelp.com/help/getting-started-with-equatio
https://support.texthelp.com/help/getting-started-with-equatio-windowsmac
Myscript Math Add-On for Word
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