Sudoku Mathrax - 200 Master Puzzles 9x9 (Volume 25)

Mathrax consists of a square grid.
The goal is to fill in each cell with numbers from 1 to N, where N is the size of the puzzle's side.
No number may appear twice in any row or column.
Circles with additional conditions may be situated on intersections of lines inside the grid. A number and a sign of mathematical operation (addition, subtraction, multiplication, division) - a number is a result of an operation execution with numbers in diagonally adjacent cells.
A letter "E" ("even") - all numbers in four cells are even.
A letter "O" ("odd") - all numbers in four cells are odd. The puzzle book contain:
- 200 Puzzles
- Handy 6 x 9 inch Book Layout
- 2 Puzzles per Page
- Ideal for Experts In the book you will find a description and examples of solutions for all puzzles.
The book is for those who like logic and math problems. Decide, developing and improving.