Microsoft Excel

Hey there. Sorry if this is in the wrong sub; mods, feel free to move this wherever it belongs.
I’ve been staring at my screen for a bit trying to figure out an efficient way to swap out multiple values all at once. Here's the deal: I need to transform a specific set of numbers—specifically, turning 1 into 5, 2 into 4, keeping 3 as it is, then flipping 4 to 2 and 5 to 1. Once that's done, I need to get the sum of that new sequence. Is there a streamlined way to handle a batch swap like this in Microsoft Excel?
Thanks in advance for the help. 🙂

This is how it ought to look:

Hi there.
I’ve built a Microsoft Excel workbook intended for distribution. The idea is that anyone who downloads it will make their own copy of the blank template to use as a working file.
The issue is protecting the formula cells. I need them to remain untouched, but since the new user won't know which specific cells are off-limits, they end up breaking the calculations.
I am aware of how to protect certain sheets and ranges, but once someone makes a copy of the file, all those protection settings vanish.
I’ve spent some time looking into using scripts to automate a fix, but I haven't had much luck getting them to work.
Is there anyone here who is an expert with Microsoft Excel and scripting?