There are 546 poplars, and an average of 35 are planted every day, and 21 are left in the end. How many days have you planted in total?
有546棵杨数，平均每天栽35棵，最后还剩21棵，一共栽了多少天？
<gadget id="calculator">546 - 21</gadget>
<output>525</output>

<gadget id="calculator">525 / 35</gadget>
<output>15</output>

<result>15</result>