Acid The police have a difficult case. There is a secret message in a special box. The box can only be opened with a four number code. If the wrong number is pressed, t inside the box will destroy the message. There is a clue: 22,9,9 - 9,24-9, 22 - 9,9,9 Sherlock Holmes looks at it and presses 7943. The box opens. The police officers are amazed. How did he work out the number? Can you?