There is a three-digit number equal to 42 times the sum of its digits. What is the three-digit number?
有一个三位数等于它的各位数字和的42倍，这个三位数是多少．
<gadget id="calculator">7 + 5 + 6</gadget>
<output>18</output>

<gadget id="calculator">3 * 2 * 7 * 18</gadget>
<output>756</output>

<result>756</result>