A tube of toothpaste has an outlet diameter of 5 mm, and each squeeze of 1 cm toothpaste can be used 40 times. What is the volume of this toothpaste in cubic decimeters?
一支牙膏出口直径为5毫米，每次挤1厘米牙膏，可以用40次，这只牙膏的容积是多少立方分米．
<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) / 2</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">(1/40) ** 2</gadget>
<output>1/1_600 = around 0.000625</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">3.14 * (1/1_600) * (1/10) * 40</gadget>
<output>0.00785</output>

<result>0.00785</result>