What is the difference between 30 minus the quotient of 20 divided by 4? What is the correct column formula.
30减去20除以4的商，差是多少？正确的列式是多少．
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">30 - 5</gadget>
<output>25</output>

<result>25</result>