There are 72 red balloons and 18 yellow balloons in the store. There are 9 more red balloons than blue balloons, and the number of yellow balloons is equal to the blue balloons.
商店里有红气球72个，黄气球18个，红气球比蓝气球多9个，黄气球是蓝气球的多少．
<gadget id="calculator">72 - 9</gadget>
<output>63</output>

<gadget id="calculator">18 / 63</gadget>
<output>2/7 = around 0.285714</output>

<result>2/7 = around 0.285714</result>