Scattered Sudoku (Mini Sudoku Series #90)

I wanted to introduce Disjoint Groups Sudoku to kids in my Sudoku training class. However, Disjoint Groups Sudoku is very tough to understand and then use the various rules to solve the Sudoku. Then I thought of the idea of creating the Scattered Sudoku and making them understand this Sudoku type. Later I can introduce the Disjoint Groups Sudoku puzzle as this Sudoku variation is nothing but a special case of Scattered Sudoku where all the cells are scattered in all the regions. This is the first mini Scattered Sudoku that I have created and I will be creating a few more to make them understand the rules of this Sudoku type.
This Scattered Sudoku puzzle I am posting in Mini Sudoku Series as 90th Sudoku in this series.

Rules of Scattered Sudoku

Place a digit from 1 to 6 in each empty cell so that each digit appears exactly once in each row, column outlined region, and the six grey cells.