The students went to the zoo. There were 48 people who visited the water hotel, 53 people who visited the bird hall, and 21 people who visited both halls. How many people visited the zoo?
同学们到动物园去游玩，参观水旅馆的有48人，参观飞禽馆的有53人，两个馆都参观的有21人，去动物园参观的一共有多少人？
<gadget id="calculator">53 - 21</gadget>
<output>32</output>

<gadget id="calculator">48 + 32</gadget>
<output>80</output>

<result>80</result>