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