If you are having difficulty solving this puzzle but don't want to see the answers just yet, then read the following tips. Add up all the possible numbers (in this case, 1 through 11) and then try to get the sum of all but one triangle. The difference between the two sums would get you the value of that one triangle. Also, some simple algebra can help determine relationships between two triangles; so, if you know the number for one triangle, you will immediately know the number for another triangle. Finally, take advantage of the fact that each triangle has a unique number. That way, you can eliminate possiblities. For instance, if you know that two triangles are 4 and 7 and you know that a third triangle has a number which is five higher than that assigned to a fourth triangle, then that third triangle can't be 9 because 4 was already assigned to the first triangle (not the fourth triangle).

ANSWERS: A is 7; B is 5; C is 2; D is 10; E is 1; F is 6; G is 11; H is 8; I is 3; J is 9, and K is 4.