This estimation worksheet will produce 4 digit sums and differences problems with rounding guides for the students to solve. The students will round and rewrite the numbers in the place holder to the right of each problem. You may select either tens, hundreds, or thousands for the students to round to for the problems. You may also instruct the students to solve the actual problems so they can compare the actual to the estimated solutions. You may elect to have the first problem worked out as an example.