Sure. It's easier to calculate it in the footer of the subform, but you could either use DSum to calculate the total of the records in the subform OR put the total in the subform, HIDE it (visible = no) and then just put a field in the parent form that reads its value:

=SubForm.Form!TotalFieldName

In fact, someone else recently asked me this question... I might make a video about it for TechHelp later.

See Form Footer Totals, Extended Cut