li>INTERMEDIATE (able to maintain large worksheet; freeze/unfreeze headings; work with multiple worksheets; navigate among sheets in a workbook; open/arrange multiple windows in a worksheet; move/copy info between worksheets; create summary worksheet to recap values from other worksheets; import data; add/review/edit/print comments; customize page set-up and print options; preview page breaks, etc.). Great Lakes and Great Times: Michigan boasts four Great Lakes, 11,000 inland lakes, 36,000 miles of rivers and streams, 20 million acres of forests, 100 state and national parks and recreation areas, 1,300 miles of bike trails, 6,500 miles of snowmobile trails, the second-most ski areas in the nation, 650 public golf courses, 600 campgrounds, and an international dark-sky park-just for starters.