maths oragami

in class we have been making maths origami boxes
we had to make two of them each one size A4 and one size A3
on my first one  which was A4  the measurement was 21 X 21
and I think that five postic notes can ftn on it.

and on my A3 one i predicted 10 but it was actually 12 that i ended up with 12 .