Subtract the product of 3.5 and 4 from a number, and the difference is 5.7. Find this number. How many.
一个数减去3.5与4的积，差是5.7．求这个数．多少．
<gadget id="calculator">3.5 * 4</gadget>
<output>14</output>

<gadget id="calculator">14 + 5.7</gadget>
<output>19.7</output>

<result>19.7</result>