Totally agree with Trev on that. Whether a spreadsheet or just a piece of paper with a stubby pencil, it's 5th grade math.
Another tip is to assign debts to you that you care about....and assign debts to her that you don't care about. That way if she doesn't pay them, the damage is minimized.
The spreadsheet idea can also include the bigger picture of assets of large items too, like this.

In my case, I was open for her to have things like the motorcycle, bowling ball, turbine-powered-leaf-blower at fair market price. But she avoided those pretty much as taking on big assets also meant she took on more debt.