question: 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?
answer: Travis had 61 - 9 = <<61-9=52>>52 apps after deleting the ones he didn't use.
  After downloading some more he now has 52 + 18 = <<52+18=70>>70 apps on his tablet.
  #### 70