Trio Sudoku (Fun With Sudoku #71)

Trio Sudoku is one of the easiest Sudoku types. In Even-Odd Sudoku, the puzzle is divided into two parts with each part can be solved individually. This division makes Even-Odd Sudoku very easy Sudoku variation. However, in Trio Sudoku it is divided into 3 parts with each part solvable independently. So if one wants to teach Sudoku variations to kids then Even-Odd Sudoku and Trio Sudoku should be the first few types which one should be teaching to kids.

This Trio Sudoku, I am posting as 71st Sudoku in Fun With Sudoku Series.

Rules of Trio Sudoku

Classic Sudoku Rules apply. Additionally, cells with circles must contain the digits 1, 2 and 3. Cells with squares must contain the 4, 5 and 6. Blank cells must contain the digits 7, 8 and 9.