Answer :

9

Explanation :

Taking numbers in diagonally opposite squares, calculate their sum, and put the answer in the small, inner square of the upper number. Calculate their difference, and put this answer in the small, inner square of the lower number.

Answer :

0

Explanation :

Working from left to right and reading each pair of numbers as a 2 digit value, these values represent the sequence of multiples of 7, starting at 49 and finishing on 70.

Answer :

13

Explanation :

Working in rows, from left to right, double the left hand number to get the middle number, and add 3 to this to get the right hand number.

Answer :

11

Explanation :

In each triangular group of circles, start with the longest row and add together 3 adjacent values and put this sum in the circle directly above or below the centre of the 3 values. Continue this sequence towards the apex of each

Answer :

92

Explanation :

Working from top to bottom, left to right, add together the first two numbers and subtract 3 to give the next value along.