Puzzles - Number puzzles

49.
Answer
:
3
Explanation
:
Reading each column as a 3 digit number, moving from left to right, the columns follow the sequence of cube numbers of 5, 6 and 7.

50.
Answer
:
13
Explanation
:
In each star, the central value equals the sum of the upper and lower digits on each star, subtracting the sum of the left and right hand digits.

51.
Answer
:
6
Explanation
:
In each circle, double the numbers on the left hand side and put the result in the opposite segment on the right hand side.