Yes, just made about the same calculation mistake. Was working a a couple baby quilts and needed colored coins to go around the outside of the body with 4+ white sections between. I estimated how many I needed and proceeded to start cutting them from the leftover fabrics. I needed 72 total so divided that by 6........the number of fabrics I had. What I forgot was I had 6 color families with 6 fabrics each so 36 fabrics not 6.............you see where this is going, right???? So I had 6 times x 36 too many 2.5 x 2.5 blocks. So made use of some of them in another baby quilt I was working on. Still have a small plast tote full of this little suckers though. Anyway, they will never go to waste as someday I'll need them in another quilt.........What a DUH moment!!!!