A Cross Summon is the method of Summoning a Cross Monster from the Extra Deck. Once per turn, during the turn player's Main Phase, the turn player may use 1 Augment monster in their hand and any number of monsters on the field as Cross Materials. The Level(s) of the monster(s) on the field are multiplied by the Level of the Augment Monster in the hand and they must equal the Cross Product listed in the card text of the Cross Monster you are attempting to Summon.
Cross Summoning is relatively easy to do but is limited to only being able to do once per turn.
How To Cross Summon[]
A Level 4 Augment Monster X
A Level 4 non-Augment Monster =
A Cross Product 16 Cross Monster