Calculate

By means of the calculate spell, the caster can accurately estimate the chance of success of one specific action, such as climbing a dangerous cliff, making a trick bow shot, crossing a burning room unharmed, or even striking an enemy. The priest doesn't have to be the person who attempts the feat; he can use calculate to estimate the odds for anyone taking an action in his sight.

Note: This spell originally appeared in this form in the Player's Option: Spells and Magic supplement for the AD&D game from TSR. Its use here is for the purposes of providing context for the campaign only.