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