Category

Japanese mathematics

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thumb|Bi-quinary coded decimal-like abacus representing

350px|thumb|A modern soroban. The right side of the soroban represents the number 1234567890, each column indicating one digit, with the lower beads representing "ones" and the upper beads "fives".

East Asian numeral system

thumb|A sangaku dedicated to Konnoh Hachimangu (Shibuya, Tokyo) in 1859.

Japanese mathematics

Japanese theorem for cyclic polygons

theorem that no matter how one triangulates a cyclic polygon, the sum of inradii of triangles is constant

Japanese theorem for cyclic quadrilaterals

napkin ring problem

problem in geometry

Equal incircles theorem

on rays from a point to a line, with equal inscribed circles between adjacent rays

Chinese system of algebra developed in Jin dynasty (1248)