Most spreadsheet applications have built in formulas and functions that will do the math for you so you don't have to. You can keep a running balance of your accounts and you can have each category totaled as well. You can keep it as simple or make it as sophisticated as you please.
Over time, the spreadsheet grew into what we see today, in the form of Microsoft Excel and a number of similar products on the market. The power of the spreadsheet has grown almost exponentially, allowing the user to create customised formulae, charts, pivots and so on. Worksheets can be linked and updated automatically.
You'll need to develop good marketing material. Things like demo videos, which you can find plenty examples on YouTube, screenshots, and keyword rich descriptive text help people find your spreadsheet and communicate the value that sets yours a level above the rest. Excelville.com actually allows you to upload your spreadsheet with all of this marketing material in an easily searchable and user friendly website.
When your spreadsheet start to hit its limits, what options are open to you? Perhaps the best option is to consider the conversion of your spreadsheet to a database solution. Relational databases became viable not too long after the spreadsheet was well-entrenched as the affordable and quick means of gathering data and performing calculations.
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what is a spreadsheet used for