5 years ago, I was 5 times my son's age. Today I am 3 times his age. Excuse me, how old am I now?
5年前，我的年龄是我儿子的5倍．今天我是他年龄的3倍．请问，我现在的年龄多大？
<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">15 - 5</gadget>
<output>10</output>

<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 + 5</gadget>
<output>10</output>

<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<result>30</result>