Puzzles - Number puzzles

Add together numbers in corresponding segments of the upper 2 squares, and put the results in the middle square. Numbers in the lower left square equal the product of the upper left and central squares, and numbers in the lower right square equal the product of the upper right and central squares.

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.

Starting with the 3 circles in the top row, add together values in corresponding segments of the left and right hand halves of the left hand circle, and put the results in corresponding segments of the left hand half of the central circle. Repeat this pattern for the left and right hand segments of the right hand circle. For the lower row, follow the same pattern, but calculating the differences between values in the left and right hand halves of the left and right hand circles, putting the results in the central circle.