Vedic Mathematics/Sutras/Urdhva-Tiryagbyham

< Vedic Mathematics/Sutras

Multiplication of a 2 figure integer ab by another 2 figures integer cd :

$\begin{matrix}a & & b\\ \vert& \times & \vert\\c & & d\\a*c & ad+bc & b*d\end{matrix}$

or in base 10:

(10a + b)(10c + d) = 100(a * c) + 10(ad + cb) + (b * d)

of course, the cases where (ad + cb) > 10 or b + d > 10 are to be considered.