assuming sides are not creases: you have to make a 3x3 diagram and split it, and imagine you make it with toothpicks, then remove all the sides.
you will have 12 toothpicks.
you can see where this is going..
you count the toothpicks inside a 6x6
make ratios and solve (i will not do this becuase I AM LAZY!!! also i have to sleep soon)
from the first one, you can see that x is odd.
now you do the second one.
this means 2x leaves a remainder of 3 when divided by 9.
this means x is a multiple of 3.
now, 3x divided by 25 leaves remainder of 1 from the third one.
now you do guess and check and see tht the first x is 17, the next is 42, the next is 67, and on and on
this means that the number when divided by 25 leaves remainder 17, and that it is odd.
2x is remainder of 3 when divided by 9, so the first one would be 42, then adding 225 (with some intuition), so then it would be 942 would be one, then 1167. you can double check and it all works.
HOPE THIS HELPED!