Can the calculator be incorporated into the game, maybe automatically, somehow? Like a little blurb by your 'military advisor' just next to the attack pane where you enter the target country number. As soon as you enter the number, next to it is another little number indicating 'estimated military force necessary'. If you put your mouse point over the number a little text bubble reads, "the estimated additional military force necessary to break through current target's defenses according to most recent intelligence".

And so, as a player inputs the numbers of his various forces to send on that attack, the force calculator number changes. For example, the player might see the force calculator initially at 10040 change to 7040 as he enters 3000 in the field for the number of soldiers he will use in the attack. As he enters 2500 jets, he sees the force calculator number go down to 2040. Maybe this number is in red, to indicate a warning that not enough force is being sent. After inputting 680 tanks, he sees the number go down to 0, which is in yellow, which indicates caution that probably a little more force may be needed to ensure success. And so the player decides to send along 200 more tanks than is necessary, just to make the force calculator number show up as a green -200. Confident he is most probably sending enough force to ensure success, he clicks send attack, and, yay, the noob didn't have to send all that much more force than was necessary, doesn't get as frustrated as he previously did by amount of losses, and number of failed attacks, sticks around longer, and maybe doesn't quit. EE gains in player-ship, and everyone is happier.