Weapon damage is displayed as follows: xdy+z x represents the number of dice rolled, and y is the number of sides on the dice. So to get the base damage done by a successful non-critical hit by the weapon, the game generates x random numbers between 1 and y, then adds z. For ranged weapons, the mean damage value given by the ammo is also added on (thus, the bonus given by ammo is always constant). + values at the end of the item name, as conferred by enchant weapon scrolls, add 1 damage per point of enchantment, and a blessed weapon adds an additional 1 damage.