一本书的页码从自然数 1 开始顺序编码直到自然数n。书的页码按照通常的习惯编排，每个页码都不含多余的前导数字0。例如，第6页用数字 6 表示，而不是 06 或 006 等。数字计数问题要求对给定书的总页码 n，计算出书的全部页码中分别用到多少次数字 0，1，2，…，9

-Pages of a book　the coding sequence of natural numbers begin until a natural number n. Book page layout the usual habits of each page are free of extra leading digit 0. For example, p expressed by the number 6, rather than 06 or 006 and the like. Count questions require a given book s total page number n, calculate all the pages in the book are many times used in digital 0,1,2, ..., 9