Calculating a running total in an Excel table is a little tricky, because it's not obvious how to build the formula with structured references. You can easily get the current row with the @ notation, but what about the first row in a column? You might be surprised that you can use INDEX for this.
In most cases, you'll want to take time to build clean, uncluttered charts that are easy to read. However, a quick, messy chart is a great way to "sanity check" unfamiliar data. A chart can show you patterns and outliers almost instantly. It can even show when data has been faked. Best of all, you get all of this with almost no effort.