Xiaogang bought a schoolbag in the store, the original price was 105 yuan, now it only costs 30% off, how much cheaper than before.
小刚在商店里买了一个书包，原价是105元，现在只花了七折的线，比原来便宜多少元．
<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">105 * (3/10)</gadget>
<output>63/2 = around 31.5</output>

<result>63/2 = around 31.5</result>