When I lectured on Digital Electronics at University designing a lesson was much easier the monologue way. Preparing for teaching upper stage Primary similar basic material (Binary numbers) was more of a challenge since there had to be some interactivity where the students were engaged in the learning. This is more obviously more difficult and compounded by the lack of resources such as photocopying budget.
My style is to get a theme question and hang some exercises off it. Indeed it strikes me that much suggested online lesson material excessively emphasizes tasks that can now be easily be done by a simple internet search. Indeed is such as decimal to binary conversion, being quite difficult, necessary.
Specifically the question I posed was: Why do Computers use Binary ? There is one common answered benefit of binary when compared with using decimal: noise impervious-ness. But also there is the simplicity of hardware that has only to cope with two states and the related benefit of manufacture driving down size.
I used a Google Form Quiz at the end to check understanding.