Calcudoku Puzzle

Game Description
Follow the rules and fill the grid with the correct numbers. Four levels to try and thousands of puzzles to solve!
How to Play
Each large puzzle is made up of several mini puzzles. To enter a number in the grid, tap a square to select it then tap a digit on the number pad. To remove a number, select a square then tap the C button. If you'd like a hint, tap the lightbulb. The first empty or incorrect square will show the correct answer.
The Rules
A mini puzzle consists of a bold outlined group of one or more like-colored squares. Each mini puzzle contains a number followed by an operator. The operator tells how to work with the individual digits in the mini puzzle. The number is the result of the operator. For example, a mini puzzle consisting of two squares containing the number 5 followed by an addition sign (5+) tells us that the numbers in the mini puzzle will be added together and the total will be 5. A digit can only appear once in any row or column. When the same digit appears more than once, each digit will have a red background to show that an error has been made.
Hint
Look for mini-puzzles with a single square because they are the easiest to solve. Entering a digit will help narrow down the choices for the other squares in the larger puzzle.
Tags
puzzle, sudoku
Skills
computation, logic