Divide the sum of 480 and 160 by 160, then subtract 20, what is the difference? What is the column
480与160的和除以160，再减去20，差是多少？列式为多少
<gadget id="calculator">480 + 160</gadget>
<output>640</output>

<gadget id="calculator">640 / 160</gadget>
<output>4</output>

<gadget id="calculator">4 - 20</gadget>
<output>-16</output>

<result>-16</result>