Elizabeth has 10 reusable water bottles. She loses 2 water bottles at school. Then someone steals 1 of her water bottles at dance practice. To avoid any future theft of her water bottles, Elizabeth places 3 stickers on each of her remaining bottles. How many stickers does Elizabeth use in total on her water bottles?
Elizabeth has 10 - 2 - 1 = 
<gadget id="calculator">10-2-1</gadget>
<output>7</output>
7 water bottles.
Elizabeth uses 7 * 3 = 
<gadget id="calculator">7*3</gadget>
<output>21</output>
21 stickers.

<result>21</result>