Puzzles - Missing letters puzzles

Start with the top left square and move clockwise around the others. The sum of the numerical values of the letters in each square follows the sequence 20, 25, 30 and 35.

Start with the top left circle, and move in horizontal lines from left to right, top to bottom, across all 4 shapes. Letters are written in alphabetical order, in steps of 5 letters at a time.

Start at the top left segment of the left hand circle and move clockwise, then to the middle circle and move anti-clock- wise, and finally to the right hand circle and move clockwise again. Letters are written in alphabetical order, in steps of 4 letters at a time.