Buying a bottle of ink costs 1 yuan and 80 cents, and 3 pencils cost 1 yuan and 50 cents. How much is a bottle of ink more expensive than a pencil?
买一瓶墨水1元8角钱，3枝铅笔共1元5角钱，-瓶墨水比一枝铅笔贵多少元钱．
<gadget id="calculator">8 / 10</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 + (4/5)</gadget>
<output>9/5 = around 1.8</output>

<gadget id="calculator">5 / 10</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + (1/2)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) / 3</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(9/5) - (1/2)</gadget>
<output>13/10 = around 1.3</output>

<result>13/10 = around 1.3</result>