Urdhathirygbhyam is a key Vedic-sutra, which links three manners of applying it. 'Vertically', 'crosswise' and 'vertically and crosswise'!

Vertical adding by place values is a usual manner that finds answers to multiplication. Crosswise adding is little known. A combination of both these methods is graspable in 'Urdhathirygbhyam'!

Paravartya yojayet is yet another vital Vedic sutra, which means "transpose and apply" (and also 'sequential joining'). 'Object of said joining' becomes obvious in a Vedic-2D-matrix! As Vedic-matrix virtues are little-known now, said Vedic-sutra too is little-used!

A corollary of Paravartya yojayet is "kevalaihi saptakam gunyat", which reveals object of paravatya yojayet. (ka, va, la) is (1 4 3) and 7*143 is 1001. Numbers 7 and 143 have typical mutual-recurring- digits! 1/7 is 142857 (143*999) and 1/143 is 006993 (007*999)!