Kimchi Cardigan




In each of the “corners” of three stitches which form the arm hole you are still working each of these three stitches, not just the middle one.

The author's reference of “ across to center st of next 3-sc group” implies you are only working the center of this group when in fact you are working the whole set of three then skipping the remaining stitches on that short side to form the arm hole.  

By working one more stitch in the corner 3sc clusters you will get to the total 172.