While taking a practice standardized test (Minnesota Comprehensive Assessment / MCA), my students were challenged by a problem where you had to add values so the mean would be equal to a given value. My students were overwhelmed with how hard it was to solve it, so I created this worksheet to help them practice an easier method than adding up all of the values. Basically, students figure out how far away an X is from the given mean. They number of units away gives it a value. You can have students total up the values on each side, or cross out Xs that are the same distance away on each side and total up the leftovers.
1 page explanation with pictures, plus 3 pages of practice.