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Published on Apr 25, 2008
For a complete lesson on estimating sums and differences, go to http://www.MathHelp.com - 1000+ online math lessons featuring a personal math teacher inside every lesson! In this lesson, students learn to estimate a sum or difference by first rounding each number to the place specified in the problem. For example, to estimate 4,909 + 3,217 by rounding each number to the nearest thousand, first round 4,909 up to 5,000, and round 3,217 down to 3,000, then add 5,000 + 3,000 to get 8,000.