The performance team originally had 64 students lined up in a square team, and now we need to add one person to each row and column of the square team. Do the math, how many more students do you need?
表演队原有64名同学排成方队，现要使方队的每行每列都增加1人．算一算，需要增加多少名同学？
<gadget id="calculator">8 + 1</gadget>
<output>9</output>

<gadget id="calculator">9 * 9</gadget>
<output>81</output>

<gadget id="calculator">81 - 64</gadget>
<output>17</output>

<result>17</result>