For exotic and handspun yarns

In a fancy stitch pattern, what does it mean when it says this stitch is a Multiple of 17 plus 2, or Multiple of 4 plus 1.

What does a "Multiple of 17 sts plus 2" mean?

It means that there are always going to be two extra stitches at the end of the row to finish up the pattern. If you only repeat the pattern once across the row (like if you were knitting a swatch), you would be knitting over 19 stitches (17+2)

If you want to repeat the pattern across 5 times, you will need 87 sts --first you multiply 5 times 17, then add two.

If you want to repeat the pattern 15 times, you multiply 15 times 17, and then add two (257)

How about a "Multiple of 4 sts plus 1"?

It means the same thing. You repeat a multiple of 4 across the row, and then finish up with that last little stitch. The reason you are given this little math problem for each knitting stitch is so that you will cast on the right number of stitches.

Just thinking about it will drive your mind crazy. But if you take the time to knit up a few swatches you'll start to understand why this works. Many patterns, especially the more exotic lace patterns, need to close off the final edge so that they look nice.

Just try it, you'll see that it works.