History of Hindu Mathematics: A Source Book v1.c8.s6.t1.1

v1.c8.s6.t1.1

The identity
(i) n² = (n - a)(n + a) + a² has been mentioned by all Hindu mathematicians as affording a suitable method of squaring in some cases. For instance, $15² = 10 × 20 + 25 = 225.$