The Association of Teachers of Mathematics have produced a series of short video clips. (Very short – they are less than 3 minutes long!) They are a fantastic mixture of easy to use games, tasks and activities and there is something for everyone. They were designed by the experts to use in lockdown and you could use them anywhere including as fun homework activities.
Here’s the link to access them: Maths Snack Videos
Here’s an example of one of their videos but there are plenty of others covering a range of different ideas: