The teacher took a few students to make flowers. The teacher made 21 flowers, and the students made 5 flowers on average. If teachers and students count together, it happens that each person made 7 flowers on average, how many students are making flowers?
老师带着几个同学在做花，老师做了21朵，同学平均每人做了5朵．如果师生合起来算，正好平均每人做了7朵，求有多少同学在做花？
<gadget id="calculator">21 - 7</gadget>
<output>14</output>

<gadget id="calculator">7 - 5</gadget>
<output>2</output>

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<result>7</result>