Sashing and checker board border help please
I have 9 x 9" blocks (seam allowance of 1/4" so blocks are actually 9 1/2") I need to join the blocks with sashing of two inches on all sides so the actual strips I cut will be 2 1/2" I believe. The I need to surround the nine blocks complete with the sashing with a checker board border that is approx 4" wide so two rows of squares. i need the squares to line up with the 9" blocks. Can someone kindly tell me the maths for cutting the checker border please? I want to use the tear method in which I stitch stripes together then cut to turn to restitch into the checker board.