1. Do this: \(\text{There are 5 available options: xxxxx.} \\\text{These are the possible combinations: 24xxx, x24xx, xx24x, and xxx24} \\\text{it follows that: } \\10\cdot10\cdot10=1000\\ 9\cdot10\cdot10-1=899\\ 9\cdot10\cdot10-1=899\\ 9\cdot10\cdot10-2=898\\ \text{The answer is } 3696\)
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