Numeration is either the act of counting, or a system for counting and writing numbers. “Decimal numeration” means the way we count in tens, with the digits 0 to 9. You will meet the word in older maths books and in formal writing. In class, teachers more often say counting or number system, and that is what people say outside school too. It is not a word for “being good at maths.” That is numeracy. Numeration is the process, or the method, of numbering things. A child pointing at toys and saying “one, two, three” is doing numeration in the first, simple sense. A book that explains how place value works is talking about a system of numeration.

計數；計數法