Puzzles - Number puzzles

Answer

:

3

Explanation

:

In each diagram, the sum of the top two and middle digits equals the sum of the lower 2 digits.

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.

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.