To practice rounding numbers, visit one of several websites that have practice problems and worksheets available, such as Khan Academy and IXL. The IXL site allows visitors a certain number of practice rounding problems per day, after which users can continue after registering for the site. Away from the Internet, printed worksheets can serve as practice, as can rounding numbers that pop up during the course of a day.
Rounding is useful in estimating calculations for resources needed, monetary values or measurements. For example, during the early consideration phase of building a house, building or stadium, a ballpark estimate of the time and money involved is necessary to determine whether the project is feasible. In such a case, making estimates is important to move forward.
A good use for rounding occurs when figuring annual income from possible jobs that pay hourly. A simple rule of thumb is to multiply the hourly rate by 2,000, as that is roughly 50 weeks times 40 hours per week. Those numbers can vary greatly from week to week or throughout the years, but for simple comparisons with jobs offering annual salaries, the method suffices.
Finally, rounding becomes important in measurements that involve finding significant figures. This process is a means to ensure that any digits that arise from simplifying fractions or irrational numbers are meaningful, and not just by-products of the calculation. When figuring out where to cut a board or how much liquid to add to a recipe, any result beyond tenths of an inch or a quarter ounce is often not important or not measurable.