Now the age of the father is 3 times the age of the son and 4 years less. In another 10 years, the age of the father will be twice the age of the son. How old is your father now?
现在父亲的年龄是儿子的3倍少4岁，再过10年，父亲的年龄是儿子的2倍．现在父亲多少岁．
<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">20 - 10</gadget>
<output>10</output>

<gadget id="calculator">4 + 10</gadget>
<output>14</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<gadget id="calculator">14 / 1</gadget>
<output>14</output>

<gadget id="calculator">14 * 3</gadget>
<output>42</output>

<gadget id="calculator">42 - 4</gadget>
<output>38</output>

<result>38</result>