"The story takes place in Sorcery City where everything, from frying eggs to mathematics, is conducted by magic. When a mathemagician wants to add to numbers, he must summon mystic spirits, which represent the numbers. One day, a young mathemagician summons a zero to be added to a six. A ghost floats in, hovers over the six, and floats away, leaving the six unchanged. The older mathemagicians, not realizing the existence of zero, insist that the apprentice be taken to court and tried for his unauthorized antics.

The judge confronts the apprentice: "Zero is another name for nothing, isn't it? How can there be a spirit of nothing? If you cast spells for spirits that don't exist, the spirits might get mad."

Insisting that zero exists, the accused demonstrates with magic spells that zero has definite properties in addition and subtraction. But he hesitates over the division spell, because he doesn't know "what the zero spirit will do." When he does summon the ghostly zero spirit, it swoops past the numeral six, and the six crumbles and falls apart (because the outcome of dividing with zero is undefined).

At last the symbol for zero appears in the multiplication spell, and the judge is convinced that zero does exist. The spectators applaud the young mathemagician, and zero joins the number system." - Summary from the teacher's guide.

Part of the Exploring Mathematics series.