Mathrax - Sudoku and Maths

Mathrax is a logic puzzle. 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 appear 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.
**** Mathrax features ****
# Content
- 6 different sizes of board
- 5 difficulty levels
- more than 500 levels
# Features
- Highlight wrong number automatically
- Autosave the process of unfinished levels
- Record best completion time for each level
# Challenge
- Game Center Achievements
- Try to complete as many levels as possible