Write each place value from the word form as digits, then combine.<br><br>
&bull; Thousands: Forty-two thousand = 42 × 1 000 = 42000<br>
&bull; Hundreds: nine hundred = 900<br>
&bull; Tens and ones: fifteen = 15<br>
&bull; Combine: 42000 + 900 + 15 = 42915<br>
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Final Answer: 42915