I hope someone is on to help me. I’m stuck. I’m doing Silver’s tutorial. I have my 20 rows of making my heel flap and have 20 stitches on the needle as I’m doing worsted weight instructions. I’m at turning the heel. It says to purl to two stitches beyone the center (of 20) which is 12 stitches. Then it says to purl 2 stitches as one which leaves fourteen stitches left to work. It the says to purl one more stitch and I will have purled 18. That doesn’t add up to eithteen. 12 + the two purled together (2) plus one more is only 15 stitches purled total, not the 18 is says I should have purled. What do I do?