# Math tapestry puzzle #1

I went outside. I saw several math tapestries. Apparently they mean something. What goes in spot NN? I know from my friend that...

• Two adjacent numbers always have the same sum.
• The 4 numbers in each of the 3 by 3 squares always have the same sum. The 3 by 3 squares are aligned in a grid.
• This one has a number set from 0 to 30.
• No number is used twice.
• Not all numbers are used.
• Adjacent does not include diagonals.
• All the letters are variables. I've doubled letters to accommodate 2-digit numbers.
   04       02
18    17 aa    13
bb       15
26       16
11    06 cc    03
NN       00

• Welcome to the site! A few things I don't understand: (1) What does "Two adjacent numbers always have the same sum" mean? The top left number, for example, is adjacent to both 04 and 18, so it can't be either that two adjacent numbers must have the same digit sum as each other or that the sum of two adjacent numbers is always the same thing. (2) You've given us a 6x6 square of numbers; how can it use numbers from 0 to 30 without any number being used twice? (3) What does "The other letters are variables" mean? a,b,c are variables but x isn't? Mar 12, 2020 at 12:18
• Welcome to the site! I have a few questions: How is it possible that no number is used twice, if there are 36 spots on the board, but the allowed numbers are from 0 to 30? Also, what do you mean by "other letters are variables" - is the variable "a" or "aa"? If you use a "variable" can that repeat a number? For example, if "a" is equal to 1 and then "aa" is equal to 11, is that ok, when there's already 11 in the grid? Mar 12, 2020 at 12:20
• Gotta fix it again! Thank you for the information. Mar 12, 2020 at 12:35
• "4 numbers in a 3 by 3 square always have the same sum. The 3 by 3 squares are aligned in a grid." There are no such squares. Mar 12, 2020 at 12:50
• I presume by "square" you mean each of the four diamond-oriented squares (which remain after deleting the unused xx blanks). The 3x3 squares you mention might overlap? Mar 12, 2020 at 12:52