If x=18, and x is 3 less than y, then how much is x in y. (fill in a fraction)
如果x=18，且x比y小3，那么x是y的多少．(填几分之几)
<gadget id="calculator">18 + 3</gadget>
<output>21</output>

<gadget id="calculator">18 / 21</gadget>
<output>6/7 = around 0.857143</output>

<result>6/7 = around 0.857143</result>