XXX x 12 (any number times with 12)

Formulas :

add 0 at the start and end of the number.

Example :

12 x 314 = 03140

Divide them to 2 in a group.

(0 x 2) + 3 = 3

(3 x 2) + 1 = 7

(1 x 2) + 4 = 6

(4 x 2) + 0 = 8

So, 12 x 314 = 3768