The hammer rang once. A spark jumped off the anvil and did not go out. It waited. They followed.

It rolled across the Green and stopped on the step of a painted wagon. The wagon had not been there at breakfast. Gold letters on its side said THE OPEN HAND.

One wheel of the wagon had a new spoke, paler than the rest. Someone had scratched a tiny hammer on it.

A trunk sat on the roof. It had seven locks, all shut.

"Magicians," said Beto. "I could take that trunk apart."

"Magicians fool people," said Danya. He was twelve, and he did not like being fooled. "How do we know anything they do is real?"

Nabo stepped down from the wagon in a bright patterned sweater.

"Pick any three digits and don't tell me," said Nabo. He turned his back.

Beto wrote 742 in the dust with a stick.

"Reverse it and take away," said Nabo. "The smaller from the bigger."

Beto wrote 247 under it. Seven hundred and forty-two take away two hundred and forty-seven. He worked it out slowly. 495.

"Now reverse that and add," said Nabo.

495 and 594. Beto added them. His mouth fell open.

"One thousand and eighty-nine," said Nabo, still facing the wagon.

A man in a velvet waistcoat clapped from the doorway. That was Marlow, who ran the show.

Danya folded his arms. "He saw it. Or it's a trick number."

"My turn," said Danya. "Watch this."

He picked 545. Reverse it: 545. Take away: nothing at all.

"See?" said Danya. "Zero. Your trick is broken."

Nabo turned round. He did not look upset. "Every road comes home to the same door," he said. "But the first and last digits have to be different. Yours were both five."

Danya's ears went hot. He had not read the rules. He had only wanted to win.

"Fine," he said. "Then I'll find out why it works."

That evening the troupe rehearsed. Beto was allowed to help.

He picked 413. Reverse: 314. Take away: 99. Reverse 99: still 99. Add: 198.

"It broke again!" said Beto.

Elvi came running from behind the curtain with a stick of chalk.

"There is always room in the middle," said Elvi. "Keep the zero in its place. Three digits went in. Three must come out."

Elvi wrote 099 on the board. Its reverse was 990.

Beto added them. 099 and 990. One thousand and eighty-nine.

"Don't squash the number," said Elvi. "Open it up and look inside."

Danya sat on an upturned bucket. He wanted Marlow to just tell him.

Marlow did not. "Write down what you got each time," he said. "Every difference. Then look."

So Danya watched every rehearsal and wrote.

"What do your answers have in common?" asked Marlow. Then he went to fix a lamp.

The show was at dusk. Half the Green came. Nabo did the trick three times. Three times the crowd gasped.

Then Marlow bowed and stepped back. "And now," he said, "the best part comes after the bow."

Danya stood up. His knees felt wobbly. He held up his list.

"Look at the differences," said Danya. "They are all 99, or two 99s, or three. 495 is 99 times 5."

He pointed. "Every one has 9 in the middle. And the two ends always add up to 9. Four and five. Six and three."

The crowd was quiet.

"So when you add it to its mirror," said Danya, "you always get nine hundreds, eighteen tens and nine ones. 900 and 180 and 9."

He wrote it on the board. 1089.

"It was always going to be 1089," he said. "That's not magic. That's the reason."

The crowd clapped louder than for the trick. On the roof, the first of the seven locks clicked open.

Back on the Green

The spark dimmed to a warm dot and settled back on the anvil. The Green was just the Green again.

The next day, Danya did the trick for his little cousin. She gasped.

Then he showed her the list, and waited, and let her find the 9 in the middle herself.