pagetutor.com - HTML tutorials for the rest of us


  1  3  8 19 ?
  5 14 35 80 ?

  first row
    1
    1 * 2 + 1 = 3
    3 * 2 + 2 = 8
    8 * 2 + 3 = 19
   19 * 2 + 4 = 42 <-- missing number
  (42 * 2 + 5 = 89)

  second row
    1 * 2 +  3 = 5
    3 * 2 +  8 = 14
    8 * 2 + 19 = 35
   19 * 2 + 42 = 80
   42 * 2 + 89 = 173 <-- missing number


  42 + 173 = 215