Four small rectangles of the same size and a square form a large square, the area of the large square is 64 square meters, and the area of the small square is 4 square meters. What is the area of the small rectangle?
四个大小完全相同的小长方形和一个正方形围成一个大正方形，大正方形的面积是64平方米，小正方形的面积是4平方米．小长方形的面积是多少？
<gadget id="calculator">64 - 4</gadget>
<output>60</output>

<gadget id="calculator">60 / 4</gadget>
<output>15</output>

<result>15</result>