According to 120/2=60, 58-16=42, 60-42=18, what is a comprehensive formula?
根据120/2=60，58-16=42，60-42=18列出一道综合算式是多少．
<gadget id="calculator">120 / 2</gadget>
<output>60</output>

<gadget id="calculator">58 - 16</gadget>
<output>42</output>

<gadget id="calculator">60 - 42</gadget>
<output>18</output>

<result>18</result>