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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Super easy (0)

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

Difficulty: Very easy (0)