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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Easy (0)