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

Difficulty: Very easy (0)

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

Difficulty: Super easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)