According to 74-9=63, 21/3=7, 63-7=56, how much is a comprehensive formula.
根据74-9=63，21/3=7，63-7=56，列一道综合式多少．
<gadget id="calculator">74 - 9</gadget>
<output>65</output>

<gadget id="calculator">21 / 3</gadget>
<output>7</output>

<gadget id="calculator">65 - 7</gadget>
<output>58</output>

<result>58</result>