tricky riddle

[corinth748]

if 1981 becomes 1861 what does 1809 become?

[shooty]

6081

[rowanwitch]

6081

[Celticv11]

1689. Or. 6081?

[shooty]

invert the numbers

[RATTER15]

6081

[Celticv11]

Or minus 120?

[factor-fiction]

Or 1689 if the rule is subtract 120

[HowardKennitby]

1089 or 1689 or 6081 depending on which transformation you are applying.

[zebo]

1089 0r 6081, the latter's more straightforward, a 180 degree rotation