Shaping arm holes, dec. with a cable pattern?

I am somewhat befuddled by the wording of a step in this pattern, I almost feel like I have to be a mathematician too!

Okay so the pattern has a 17 row cable panel set, I can do these absoultely fine until it says this:

“Keeping continuity of rev st-st with cable panel as set proceed as follows:-

Shape Armholes
Work 4 rows dec 1st at each end of every row. (67 st.)

Cont. without shaping until armholes measure 20cm ending with ws row”

What it seems to me is you have to decrease the rows whilst repeat the cable set, but do you then have to work out the first and last amount of stitches in each row? (and change the numbers on the cable pattern?)

for example if it said “p20,k3,T5L, p20” then I’d have to change it to “p19, k3, T5L, p19”? This seems overly complicated, but if I keep the pattern the same whilst decreasing wont it throw the cable off?

Could anyone shed some light for me? I really want to get stuck into this today but I cant proceed in case I do it all incorrectly!

You’ve got the idea. You’re decreasing one stitch at each end on every row for 4 rows. So the row following your p19, k3, T5L, p19 example would have you work 18sts on either side of the cable and the next would have 17sts and then 16sts. You’re only changing the sts at the sides of the cable, so far, not the cable itself or the placement of the cable. Keep the cable itself and as many of the flanking sts as possible continuous. You don’t really have to work out the number of sts so much as look at and continue the pattern you’ve set up on previous rows.

Thankyou very much :slight_smile: