Travis had 61 apps on his tablet. He deleted 9 apps he didn't use anymore and downloaded 18 more. How many apps are on his tablet now?
Travis had 61 - 9 = 
<gadget id="calculator">61-9</gadget>
<output>52</output>
52 apps after deleting the ones he didn't use.
After downloading some more he now has 52 + 18 = 
<gadget id="calculator">52+18</gadget>
<output>70</output>
70 apps on his tablet.

<result>70</result>