A square is cut off by 4 cm on one side and 5 cm on the other side. The remaining area is 160 cm2 less than the original area. What is the area of the original square in cm2?
一个正方形，一边剪去4cm，另一边剪去5cm，剩下的面积比原来的面积少160平方厘米，求原来正方形的面积是多少平方厘米？
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">20 + 160</gadget>
<output>180</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">180 / 9</gadget>
<output>20</output>

<gadget id="calculator">20 * 20</gadget>
<output>400</output>

<result>400</result>