Grammage are the same weight paper having different cut size. However, a sheet of common copy paper that has a basis weight of does not have the same mass as the same size sheet of coarse paper (newsprint). In the former case, the standard ream is 500 sheets of paper, and in the latter, 500 sheets of paper. Here are some basic ream sizes for various types of paper. Units are inches except where noted. Sheets can be cut into four sheets, a standard for business stationery known conventionally as "letter sized paper". So, the ream became commonly used. The book-paper
Ruled paper lighter lines 2 mm (appx. 5/64 in) apart between each pair of heavy lines. Heavy vertical lines are spaced 8 mm (appx. 5/16 in) apart, beginning 16 mm (appx. 5/8 in) from the left-hand edge of the page. These sheets of paper are generally known as "grands carreaux" (large tiles) as opposed to the "petits carreaux" (small tiles) which are 5x5mm. Seyès ruled paper is available in single sheets ("copies simples") or joined double sheets ("copies doubles") which are sometimes preferred for exams, being easier to handle. DIN 16552:1977-04 (“Lines for handwriting”) specifies the types of ruled paper to be