This is a set of two worksheets to be assigned or completed within the piano lesson, after Bass D has first been introduced.
I find that if notes are highlighted along the way students usually notice more about them and see them as individual characters, so that they can be identified more quickly and confidently later. The first worksheet here is to search for and identify bass D, and the second to practice drawing them out, which creates further familiarity.
The full set of Buggy Bugston theory worksheets for primer level students is available with US terminology on Teachers Pay Teacher here or with UK terminology on Teachers Pay Teachers here. It’s a great supplement or assignment for primer level students.