With Excel, you can easily round your numbers to the nearest tenth, hundredth, or thousandth. The technique explains in this article.
How to round up or down for decimals, like for instance, 10 cents, 25 cents, 50 cents? The different formulae explain in this article
How to round up by 10, 25 or 50 in Excel? This article gives you all the formulae to do this job with Excel.