A rectangular vegetable field with an area of 420 square meters. Now increase its length by half, what is the enlarged area in square meters?
一块长方形的菜地，面积420平方米．现在要把它的长增加一半，扩大后的面积是多少平方米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + (1/2)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) * 420</gadget>
<output>630</output>

<result>630</result>