Originally Posted by catmcclure
This is a 5x5 block - each section is undoubtedly 2" finished. If you make each section 2-1/2" finished you will end up with a 12-1/2" block. It's easier to cut the strips 3" and end up with a 12-1/2" finished block than to try to make a 12" block.
This is what I would do. Just remember to add 1/2" to every measurement in the cutting stage of your pattern.