Inspired by playing the excellent Sumaze! 2 game from MEI, here is an investigation that aims to provide some purposeful practice on decimals. The aim is to provide an accessible entry point for all learners with opportunities for depth through generalisation. This slide presentation steps through it although exactly how you move from one part to the next will, of course, depend on the class.
I have included solutions in this spreadsheet although I would be hesitant to display them in this form, as I would prefer that the results are found and discussed as we go along rather than just revealing them at the end.