Pattern stitch help from Knitting the New Classics

I finally found a pattern for a sweater that I want to make for myself and I cannot for the life of me get the pattern stitch right! It is from the book “Knitting the New Classics” and it is the sweater pattern Festival of Color on page 146 in case anyone has the book. The pattern stitch is called an afghan stitch and there are two versions of it - garter and stockinette. I began by trying to make the swatch - cast on 26 stitches as the pattern stitch is a multiple of 12 + 3. Here are the directions for the afghan stitch in stockinette:
Row 1: (RS) K1, ssk, *k9, sl2, k1, p2sso; rep from *, end k9, k2tog, k1.
Row 2: P1, * p5, (p1, yo, p1) in next st, p4; rep from *, end last repeat p2.
In the book they say the ssk is slip, slip, knit. Well, if I do this the stitch count is off and the pattern does not work. Can someone help me figure this out - what am I doing wrong? I can’t figure it out and having my two youngest kids here bugging me the enitre time is not helping LOL! Also, when doing the swatch, should I do just the stockinette, the garter, or a combination of the two? The book does not specify, it just says afghan stitch on larger needles: 24 sts and 24 rows = 4".
TIA,
Mary

[size=2]edit - [color=violet]mod squad was here[/color][/size]

I’m thinking that if the pattern is multiples of 12 + 3 then you would be casting on 27 stitches. Hope that helps.

You are right! I typed it wrong (the kids were driving me bonkers and I can’t think straight!), I did cast on 27 and then ended up with 26 at the end of the row. I will try it again though when they go to bed and see if I can figure out the problem yet.

Anyone else have any suggestions? Thanks!

Well first of all, ssk is a decrease, not just slip, slip, knit. It’s a decrease here.

I have this book. For your swatch, you probably should work 6 rows in the AGS and 6 rows in the AST until your swatch is big enough, since that’s the way the pattern goes. That should get you a close enough measurement anyway.

Thank You! Now why in the world would they not just say in the book that its a decrease?? I am not new to knitting by any means (about 20 years now!) and I usually do not have any problems with patterns, even complicated ones. Most patterns I have ever used are a bit more explicit in their directions I guess LOL. I will try again today.
Thanks much,
Mary