David Watkins has provided an extensive, easily searchable collection of Excel Mathematics worksheets on dynamicmaths.co.uk. As you can see from the above image (his Algebra-01 sheet on simplifying linear expressions), these worksheets can be customised to suit a particular class. As well as a class activity, these could make excellent starters or plenaries, I think they would also be useful for student self-study / revision.
I find these ideal for ‘Bell Work‘ as I can easily snip a screenshot and create a worksheet for students to complete as they enter the room. (I also create a PowerPoint or flipchart ahead of time with the questions displayed without and with answers)