On this page, you can practice estimating the result of addition and subtraction problems, and then calculating the exact answer. Use your estimate to check that your final answer is reasonable.
For each question, we provide an interactive grid paper where you can calculate the sums and differences, just like you would using pencil & paper.
To come up with the estimate, you should round the given numbers either to largest place that the numbers have, or to the second largest. For example, if the question has three-digit numbers, round them either to the nearest hundred or to the nearest ten. The script will not tell you how to round, and it will accept estimations based on these different types of rounding as correct.
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