Use a piece of rectangular red paper with a length of 20 decimeters and a width of 12 decimeters, and cut it into an isosceles right-angled triangle flag whose right angle is 4 decimeters. How many small flags can be made at most?
用一张长20分米、宽12分米的长方形红纸，剪成直角边是4分米的等腰直角三角形小旗．最多可以做多少面小旗？
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">5 * 3 * 2</gadget>
<output>30</output>

<result>30</result>