For a spell to be cast, the total of the dice rolled, must equal or beat the spell's casting value.
The chosen dice are then taken from the casting player's power pool and rolled. The results are then added together, to give a casting result. Keep the dice in front of you for the moment – you'll need the scores if your opponent attempts a dispel, as we'll discuss later.
Each spell has an associated casting value, any number from 3 upwards. Spells with a higher casting value have greater effect, but require more power.
If the casting result equals or exceeds the spell's casting value, the spell is cast (though it may be subsequently dispelled and neutralised by the opposing player, as we'll discuss later).
If the result is less than the casting value, the casting attempt has failed. The spell is not cast.