Cristina, John, Clarissa and Sarah want to give their mother a photo album for her birthday. Cristina brings 7 photos, John brings 10 photos and Sarah brings 9 photos. If the photo album has 40 slots available, how many photos does Clarissa need to bring in order to complete the photo album?
Excluding Clarissa, there are 7 + 10 + 9 = 
<gadget id="calculator">7+10+9</gadget>
<output>26</output>
26 photos.
Clarissa needs to bring 40 - 26 = 
<gadget id="calculator">40-26</gadget>
<output>14</output>
14 photos to complete the photo album.

<result>14</result>