I'm computer savvy but never really took the time to learn Microsoft Excel. I would like a chart that I can keep track of my paracord stock in. Maybe something that has all the colors listed across the top, and then in the row below that my initial length that I have in stock. I would then like it if I could then enter in the amount of cord I use in each color for each item I make and Excel would automatically do the math and figure out how much cord I have left. Does that make sense? For example:

Color - red

Beginning length - 350'

Length used - 25'

Length used - 15'

Length used - 35'

Length remaining - 275'

But I want it to do the math for me. Is that possible? And if it is, HOW?