Thank you so much for answering. I am still very much a beginner. In effect, how would that apply to:

D17 =SUM(Sheet1!$C6:$BB12)
D18 =SUM(Sheet1!$C13:$BB19)
D19 =SUM(Sheet1!$C20:$BB26)

then D20 returns =SUM(Sheet1!$C9:$BB15) when I autofill.
Sorry about the multiple questions, I am right on the cusp of comprehending this. I appreciate both of your responses