Divide a number by 4 and then subtract 20 to get 140. What is the number?
一个数除以4后再减去20得140，这个数是多少．
<gadget id="calculator">20 + 140</gadget>
<output>160</output>

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

<result>640</result>