Pay Down Debt First, or Keep Savings Intact?

My mother has offered to give us a small amount of money, which we can either use to pay down most of our debt, or we can put into a savings account, and then pay down the debt over time.

My wife and I have been debating which is the better course of action. After playing around in Excel, I decided to write a script to help us resolve this issue. See https://davidwees.com/javascript/debtsavings/. 

I also gave this problem (with the actual numbers my wife and I are looking at) to my 12th grade students as part of our review for their IB exams in May. One student’s reaction, "This is a real problem? Really? Wow."

*Disclaimer: The script in question is a work in progress, it may contain bugs, and should not be relied upon to do any actual financial planning.