Help with charm square maths please
 

I'm having trouble with my brain lately :thumbdown:, and can't figure out what should be a straightforward maths problem. So I hope someone can help out :). I'm getting lost in figuring the seam allowances.

I have two packs of bright/bold Kaffe Fassett charm squares I have been hoarding for a while. What I would like to do is cut each square in half in the middle and insert a strip of background fabric. Then cut in half the other way and insert a second strip. So the charm square ends up as a square with a + in the middle. Then I would like to alternate the charm squares with background fabric squares the same size.

If I add a 1" strip, is my maths right in thinking that the charm square would return to 5"? In which case I could use solid charm squares for the background fabric.

If I add a 2" strip, what would be the charm square unfinished size? (ie the size that the background square would need to be?)

I did see a pattern for the type of thing I'm talking about, but it didn't use charm squares and I'd like to use them. This photo is what I am talking about (the group of four small squares only) https://www.flickr.com/photos/279780...in/photostream

All suggestions gratefully received :thumbup: Thank you

If you add a 1" strip vertically and horizontally, you will end up with a 5" square unfinished.
If you add a 2" strip...you will end with a 6" square unfinished.

Thanks EasyPeezy. Seems obvious now I know the answer...

when in doubt, make one from scraps. my motto!