Don Colton's Risk Dice Roller

(Risk is a trademark of Parker Bros / Hasbro for their board game.)
Wikipedia Article, Attacking

How many attacking armies
How many defending armies
How many skirmishes (max)

Skirmish 1   1 2 3   2 3 attacker loses X, defender loses X
Skirmish 2   5 2 1   4 1 attacker loses X, defender loses X
Skirmish 3   3 4 1   4 1 attacker loses X, defender loses X
Skirmish 4   5 2 5   6 4 attacker loses X, defender loses X