9.3. Add a digit to the left and right of the number 10 so that the resulting number is divisible by 72.

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(5-6 \text { grade) }
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9.3. The desired number must be divisible by 8 and 9, i.e., it must be even and the sum of its digits must be divisible by 9. Only 5 numbers need to be checked: $8100, 6102, 4104, 2106, 9108$. Among these numbers, only 4104 is divisible by 72. Answer: 4104.