The school bought 170 red balloons, the number of yellow balloons is three times that of the red balloons, and the number of blue balloons is 68 fewer than the number of yellow balloons. How many blue balloons are there?
学校买来170个红气球，黄气球是红气球的3倍，蓝气球比黄气球少68个，蓝气球有多少个？
<gadget id="calculator">170 * 3</gadget>
<output>510</output>

<gadget id="calculator">510 - 68</gadget>
<output>442</output>

<result>442</result>