Naughty and everyone haven't seen each other for a year, and when they met again, everyone said that Naughty has grown taller. Naughty said: "The gate of my house is 2 meters high. My height used to be (3/5) the height of the gate, but now my height is (4/5) the height of the gate. How much have I grown in a year?"
淘气与大家有一年的时间没有见面了，再次见面时大家都说淘气长高了．淘气说："我家的大门高2米，原先我的身高是门高的(3/5)，现在我的身高是门高的(4/5)．我一年长高了多少？"
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(4/5) - (3/5)</gadget>
<output>1/5 = around 0.2</output>

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

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