Ling and fang
500 identical sheets of paper is a ream. That is to say, no matter what the specifications are, 500 sheets are taken as one order, the mantissa of less than one order is calculated by the square, and one sheet of paper is 2. That is: 1 Ling = 500 sheets = 1000 cubic meters
Stamp
A printing press prints one sheet on one side of the whole sheet and two sheets on both sides of the whole sheet. One ream of paper is 500 sheets, and two-sided printing is equal to 1000 sheets, also known as "thousand sheets". The printing sheet is the measurement unit of printing production, also used to make the measurement of the plate, which is the basis of calculating the number of books and periodicals.
Stamp and square are equal in quantity and can be converted equivalently, but they cannot be confused in meaning.
In the publishing and printing industry, to calculate the paper consumption of books and periodicals, the number of pages of a Book (or the number of pages, one page is equal to two sides) should be converted into printed sheets, and then the paper consumption should be calculated. The number of printed pages of a book is obtained by dividing the number of printed pages by the number of pages of the book, except for the cover, inserts, and Interlinings that are different from those used in the text. That is to say, the number of pages of a book printed together with the text, such as the title page, preface, catalogue, preface, appendix, postscript, etc., divided by the number of openings, is equal to the number of printed pages of the book.
Number of addends
When printing books and periodicals on behalf of the publishing house, the printing factory should not only calculate the quantity of paper needed according to the number of printed sheets and copies but also give the allowance to compensate for the loss. This is used to make up for the loss of paper, called the added number (also known as stretch number). The number of addition is generally expressed as the percentage of theoretical paper consumption, so it is also called the addition rate.