To investigate rounding more deeply, here is a structure for some questions that hopefully prompt the question, why does this happen?
Here are three examples as a pdf and as a Google doc. It doesn’t happen in the first example, but it does in the second two.
Next, see if students can create their own to investigate why this happens. I have created a blank sheet (3 on each page). Again, as a pdf document and as a Google doc.
mho maths 