The fifth grade students of Lantian Elementary School participate in the environmental protection promotion activities, and there is one more person in a group of 9 people. If there is one more person in a group of 7 people, then how many students should participate in the promotion activities at least.
蓝天小学五年级同学参加环保宣传活动，9人一组则多1人，若7人一组还多1人，那么参加宣传活动的同学至少有多少人．
<gadget id="calculator">7 * 9</gadget>
<output>63</output>

<gadget id="calculator">63 + 1</gadget>
<output>64</output>

<result>64</result>