Puzzles - Missing letters puzzles

In each square, start with the left hand segment, and move clockwise around the others. Letters are written in alphabetical order in steps of 10 for the top left square, 11 for the top right, 12 for the lower left and 13 for the lower right.

Start on the top left of the diagram and work from top to bottom in columns, from left to right. Letters are written in alphabetic order, in a repeated sequence of steps of 5, 6 and 7.

Treat each star as 2 intersecting triangles, and start on the top or the left of each triangle in each star and move clockwise around it. Letters are written in alphabetical order in steps of 6 for the left hand star, 7 for the central one and 8 for the right hand star.