There are 20 apples in a box, 7 have been eaten, how many are left? (Score representation)
1箱苹果有20个，已经吃掉了7个，还剩多少．(分数表示)
<gadget id="calculator">20 - 7</gadget>
<output>13</output>

<gadget id="calculator">13 / 20</gadget>
<output>13/20 = around 0.65</output>

<result>13/20 = around 0.65</result>