Expanding Sheets in Workbook

Hello!

I have a workbook with 54 sheets. The first four sheets are various summary sheets that pull data from the other 50 sheets. The sheets are labeled numerically.

I need to expand this workbook to 55 sheets. I can copy the sheets, rename, and reorder them easily. But is there an easier (also, less prone to omittance/error!) way to update the first four sheets to include the extras? Right now, all of the cell references say '1-50' and I need them to say '1-55.' It's multiple changes, however. I was hoping dragging formula would work once the new tabs were added and and named, but that wasn't my experience.

Help! ​