A triangle is formed with a wire 1 meter long. One side of the triangle is (1/5) meter long, the other side is (2/5) meter long, how many meters is the third side long?
用一根长1米的铁丝围成三角形．三角形的一条边长(1/5)米，另一条边长(2/5)米，第三条边长多少米？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (1/5) - (2/5)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>