Cut a small right-angled triangle from a rectangle with a length of 30 cm and a width of 20 cm. The two right-angled sides of this right-angled triangle are 3 cm and 4 cm respectively. What fraction of its area is the original rectangle?
在一张长30厘米、宽20厘米的长方形上截下一个小直角三角形，这个直角三角形的两条直角边分别是3厘米和4厘米，它的面积占原长方形纸的几分之几？
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">30 * 20</gadget>
<output>600</output>

<gadget id="calculator">6 / 600</gadget>
<output>1/100 = around 0.01</output>

<result>1/100 = around 0.01</result>