How much is it to combine 36/4=9, 12+9=21 into a comprehensive formula
把36/4=9，12+9=21合并成一个综合算式是多少
<gadget id="calculator">36 / 4</gadget>
<output>9</output>

<gadget id="calculator">12 + 9</gadget>
<output>21</output>

<result>21</result>