The "grams" actually refer to "gram per square meter". Thus, youneed to calculate the total surface of the paper (in square meters)times this number, of 80 g/m2.A "ream" is a bundle of paper,usually 500 pieces, so you need to:* Measure or read off the length and width of the paper.* Convert that to meters.* Multiply all of the following: length in meters; width inmeters; 500 (for the number of sheets); 80 (the grams per squaremeter).