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