There are 5 tons of fruits in the fruit shop, and they sell (1/10) of the total on the first day, and sell the rest (1/10) on the second day, how many tons of fruits are left at this time?
水果店有5吨水果，第一天卖出总数的(1/10)，第二天卖出剩下的(1/10)，这时还剩下多少吨水果？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">(9/10) * (1/10)</gadget>
<output>9/100 = around 0.09</output>

<gadget id="calculator">1 - (1/10) - (9/100)</gadget>
<output>81/100 = around 0.81</output>

<gadget id="calculator">5 * (81/100)</gadget>
<output>81/20 = around 4.05</output>

<result>81/20 = around 4.05</result>