Why do this problem?

This problem is one which can help learners to relate $2-D$ representations and $3-D$ shapes. It is definitely one which requires making the shapes practically from interlocking cubes such as "multilink" using the $2-D$ drawings and then recording on squared paper (preferably in colour).

Key questions

Which shape are you making now?

How can those two shapes fit together?

Which side of the cube are you recording now?

Which side of the cube comes next to that side?

Possible extension

Learners could draw the various elevations; plan view, side view etc and even cross-sections.

Possible support

Suggest making the shapes from interlocking cubes such as "multilink" in the same colours as in the problem to make it easier to tell them apart.