Mathematics in A1 is the practical, teachable layer of number knowledge that a settled community can preserve, copy, teach, and use before electronic calculators or computers are dependable. It includes written arithmetic, measuring, ratios, tables, constants, estimation, geometry for layout, and the habit of recording units and assumptions.
This branch is not meant to duplicate the higher A2 mathematics sequence. A2 covers formal algebra, geometry, calculus, statistics, and technical education for industrial recovery. A1 mathematics is the working toolkit: the tables, rules, constants, and routines that make field calculation possible with pencil, paper, slide rule, abacus, measuring stick, and printed references.
Pre-computer calculation depended on trusted tables. Logarithms turned multiplication, division, powers, and roots into addition, subtraction, and table lookup. Tables of squares, cubes, square roots, cube roots, reciprocals, sine, cosine, tangent, and common constants let surveyors, navigators, engineers, builders, teachers, and bookkeepers work faster and with fewer arithmetic errors.
Mathematical knowledge also has a memory layer. People memorized multiplication facts, common fractions and decimals, useful approximations such as pi, and simple logarithmic or trigonometric relationships. They did not usually memorize entire large table books; they learned how to use them quickly and how to check whether an answer was reasonable.
This branch supports teaching, surveying, carpentry, layout, navigation, workshop design, bookkeeping, calendrical calculation, and the interpretation of older technical books that assume table use.
Place documents here when they help people calculate without digital tools: tables, constants, practical methods, checking routines, teaching sheets, field notebooks, and historically important calculation aids. More advanced textbooks belong in the A2 Mathematics branch unless their primary use is basic community instruction.
20_A1_Stabilized_Community/Foundational_Knowledge/Mathematics