Puzzles - Number puzzles

217.
Answer
:
3
Explanation
:
In each diagram, the sum of the top two and middle digits equals the sum of the lower 2 digits.

218.
Answer
:
6
Explanation
:
In each circle, add together the left and right hand digits, and add 3 to give the value of the lower digit.

219.
Answer
:
1
Explanation
:
tart with the top left circle, and move around the others in a W shape. The sum of the numbers in each circle follows the sequence of 10, 12, 14, 16 and 18.