Chet Callas

1. The codes follow a pattern.

2. Curiously enough, it's the next day's code that leads to the previous day's.

3. How can you get 2840 from 7458?

4. Don't treat these as 4-digit numbers. Break them up and play with them.

5. How can you get 28 and 40 from 7 4 and 5 8?

6. Here's how: 4 x 7 = 28 and 5 x 8 = 40.

7. Now that you know this, use tomorrow's code to get today's.

(SOLUTION FOLLOWS)

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8. Start with 9 x 6 = 54 and then 2 x 5 = 10. The code is 5410.