Drag the numbers onto the grid so that the sum of the four numbers around a circle add up to the total given in the circle.

Well done. You have solved this puzzle. You can claim a trophy or try one of the other similar puzzles waiting to be solved.

Your answer is not correct.

12

23

15

19

10

15

20

1

2

3

4

5

6

7

8

9

Suko and Sujiko were developed by Kobayaashi Studios and permission to use the idea here has been kindly granted by their syndication agents, Puzzler.com.

Do you have any comments? It is always useful to receive feedback and helps make this free resource even more useful for those learning Mathematics anywhere in the world. Click here to enter your comments.

Ilus Osborne, Australia

Saturday, October 22, 2016

"Hi there thanks for the Suko puzzles.

Would you please generate more random patterns as the same configuration appears repeatedly and I am used to greater variety in our local newspaper - which has - unfortunately stopped featuring them.

Cheers."

Transum,

Wednesday, November 2, 2016

"Thanks for your comment Ilus. The nine numbers in the grid are positioned completely randomly by the software so there are 362,880 different possible configurations which may appear. It is extremely unlikely that you will get the same puzzle twice. Have you tried some of the other Transum puzzles yet? There are some great ones on the Puzzle Page."

Peter King, Ruscombe, Berkshire

Thursday, June 8, 2017

"The Australian comment is referring to patterns, not numbers. And yes, could you make the patters more varied please. With the same patterns keep coming up (2, 3 and 4) the puzzles are getting too easy.. Thanks."

Transum,

Friday, June 9, 2017

"Peter, please contact me with examples of the patterns you refer to. I am not sure what you mean by '2, 3 and 4'. Surely if the nine numbers in the grid are positioned completely randomly there is no further option to make the puzzles any more random... is there?"

Peter King, Ruscombe

Friday, June 9, 2017

"To answer your question: I think the puzzles are more difficult where you don't have the three colours in blocks, but scattered, especially the double one. I'm no expert technically, but that would be more difficult, wouldn't it? Anyway, whichever, I do enjoy doing them. Thank you for your website."

Transum,

Monday, June 12, 2017

"Aha… I think I now understand that the patterns referred to above are the patterns of coloured squares. The pattern for a puzzle is chosen from a set of possible patterns and the size of that set has now been increased to sixty. However, in keeping with the original idea for Suko, are limited to patterns that do not isolate single non-contiguous squares. You can see all sixty of the patterns on the Suko Patterns page."

Dennis Whiting, Herne Bay

Saturday, July 15, 2017

"I am a Sujiko fan (less so for Suko). With each new puzzle I first check the aggregate total. That is I add up all four of the circled numbers. The total of 1+2+3+4+5+6+7+8+9 =45. The central number counts 4 times because it is in each of the 4 squares. The numbers in the arms of the cross count twice because they are in 2 squares each and the numbers in the corners only count once. The lowest possible aggregate is 62 and the highest is 98. If I subtract 45 from my aggregate, the number I'm left with is the central number times 3 plus the numbers in the arms (not multiplied). This extra calculation is not always necessary to solve the puzzle but it can often be helpful."

Rob Arthan, Twyford, Berkshire, UK

Friday, November 10, 2017

"Shouldn't you be checking that the puzzles have unique solutions. E.g., I just got ((21, 21, 29, 21) which has 6 solutions. If the program I just wrote to generate them is correct, then only 8,280 of the 9! = 362880 random was of putting the digits in the grid give quadruples that have a unique solution. Or am I missing something?

[Transum: That sounds like a good program you have written Rob. When I created this page I made the decision that unique solutions weren't as important. What language did you program in?]"

Geoff, Scotland

Friday, January 5, 2018

"In the Sujiko puzzles the clues provided are always the integers 1 to n where n=number of clues. By using this algorithm the integers 6, 7, 8 and 9 never appear as clues. Can you fix it so that the clues are completely random?

[Transum: Thanks for the suggestion Geoff. It will be added to the list of suggestions for the next update.]"

Laurance Haines Primary, Twitter

Saturday, March 31, 2018