45 students from Class 1 participated in tree planting activities, and each person participated in at least one activity. In the whole class, (3/5) people participated in digging pits, and (7/9) people participated in watering. Both of these labors participated how many people?
六1班45名学生参加植树活动，每人至少参加一项活动，全班有(3/5)人参加挖坑，有(7/9)的人参加浇水，这两项劳动都参加的有多少人？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">45 * (3/5)</gadget>
<output>27</output>

<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">45 * (7/9)</gadget>
<output>35</output>

<gadget id="calculator">35 - 45</gadget>
<output>-10</output>

<gadget id="calculator">27 + (-10)</gadget>
<output>17</output>

<result>17</result>