The original price of a picture album is 6.9 yuan per copy, and now each copy is sold at 30% off the original price. How much is each picture album cheaper?
一种画册原价每本6.9元，现在每本按原价的七折出售，这种画册每本便宜多少元？
<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 - (7/10)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">6.9 * (3/10)</gadget>
<output>2.07</output>

<result>2.07</result>