A rectangular mountain land with a length of 45m and a width of 28m is planned to draw a triangular land as large as possible to plant fruit trees in this land, and plant medicinal materials in the rest of the land. How many square meters is the land for medicinal materials?
一块长45m、宽28m的长方形山地，现计划在这块地里划出一块尽可能大的三角形地种果树，其余的地种植药材，种药材的地有多少平方米？
<gadget id="calculator">45 * 28</gadget>
<output>1_260</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 45 * 28</gadget>
<output>630</output>

<gadget id="calculator">1_260 - 630</gadget>
<output>630</output>

<result>630</result>