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? Think carefully first, then make a decision:
Excluding Clarissa, there are 7 + 10 + 9 = 26 photos. Clarissa needs to bring 40 26 = 14 photos to complete the photo album. So, the answer is 14.