This can be used as a supplemental assessment or worksheet to lessons on estimating sums and differences. It can also be used as homework, if needed. This 2 page worksheet starts with an example of how to estimate the sum of 477 and 592, round each addend to the nearest ten and then add the rounded numbers. It then gives students two problems (one addition and one subtraction) to round to the nearest ten, then estimate. The next page gives a list of craft supplies with prices, along with word problems, and a higher order thinking prompt.