3		8		1
		3	5
					5	9	8
	3				4
	2		1		7		9
			6				3
	5	1	3
					9	6
6		2		4

Difficulty: Very easy (0)

7							3
			1		9	4	7
8						6
	3
		8				5
							2
		7						4
	9	6	4		7
	8							7

Difficulty: Easy (0)

	6	4				1
			7		8			4
	1			6	7		9
							7
				3
	5
	9		6	4			8
8			9		1
		7				3	6

Difficulty: Very easy (0)

			4			3
				6	5	4		8
3	9						6
							9	4
			8		6
2	8
	3						4	2
9		5	1	2
		6			7

Difficulty: Very easy (0)