Xiaohong asked Mr. Wang how old this year, and Mr. Wang said: "Add 9 to my age, divide by 4, subtract 2, and multiply by 3, which is exactly 30 years old." How old is Mr. Wang this year?
小红问王老师今年多大年纪，王老师说："我的年纪加上9，除以4，减去2，再乘3，恰好是30岁"，王老师今年多少岁？
<gadget id="calculator">30 / 3</gadget>
<output>10</output>

<gadget id="calculator">10 + 2</gadget>
<output>12</output>

<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">48 - 9</gadget>
<output>39</output>

<result>39</result>