Use the numbers 2, 4, and 7 to form a three-digit number without repeating numbers. What is the sum of these three-digit numbers?
用数字2，4，7组成没有重复数字的三位数，这些三位数的和是多少．
<gadget id="calculator">2 + 4 + 7</gadget>
<output>13</output>

<gadget id="calculator">100 + 10 + 1</gadget>
<output>111</output>

<gadget id="calculator">13 * 111 * 2</gadget>
<output>2_886</output>

<result>2_886</result>