Puzzles - Missing letters puzzles

Split the diagram horizontally into 3 rows, each 2 circles high. Start with the top left circle in each row, and move one space to the right, alternating down and up. Letters advance through the alphabet 5 letters at a time for the upper double row, 6 letters at a time for the central row, and 7 letters at a time for the bottom row.

Start at the top left and move to the right, then down one row and to the left etc in a snakes and ladders pattern. Letters advance through the alphabet 9 letters at a time.

In each circle, the digit is equal to the number of straight lines used to write the two letters in the same circle.