I avoid the math of quilting as much as possible. I have 2 charts on the wall in the sewing room: one for how many strips, squares, triangles of different sizes, etc. I can get out of a yard of fabric; and one with bed sizes, quilt sizes with or without pillow or drop coverages. Otherwise, I keep my fingers crossed and hope the pattern measurements are correct. I love it when a pattern tells how much to cut for various sizes, and provide both unit and block sizes. But darn, sometimes I have to do the math and that can take me a day or two.