The school assigned the task of planting 160 trees to the fourth, fifth and sixth grades according to the ratio of 4:5:7. How many trees should be planted in sixth grade?
学校把栽160棵树的任务按4：5：7分给四、五、六三个年级完成．六年级应栽多少棵树？
<gadget id="calculator">4 + 5 + 7</gadget>
<output>16</output>

<gadget id="calculator">7 / 16</gadget>
<output>7/16 = around 0.4375</output>

<gadget id="calculator">160 * (7/16)</gadget>
<output>70</output>

<result>70</result>