The Dice in Dungeons and Dragons decide your fate! Considering that Free Will is the aim of the game - the dice are the control!
You will roll different dice for the different actions you will take. You will play using Polyhedral dice. You refer to the dice by the number of sides each one has.
D4 - use a d4 when calculating damage from small weapons.
D6 - weapon and magic damage to recovering hit points during short rest.
D8 - calculating damage for light to medium-sized weapons.
D10 - heavy ranged weapons, some and ranged melee attack damage.
D12 - works well as a random hour generator. It is also used for heavy weapons like the great-axe or some magic weapons damage.
D20 - We use this die to see if an attempt to do something is successful or not.