Numbers Puzzles

5. Which number completes this puzzle?
  What is the next number?
Answer
6
In rows the right hand digit equals double the difference between the left and the centre.
6. Which number goes in the empty box?
  What is the next number?
Answer
14
Taking the first two lines as one group starting top left and the bottom two lines as the second group starting bottom right and moving clockwise around each one, the first number in the top group is doubled to give the corresponding value in the second group, the next is halved etc.
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