Posted in Knitting

knitting algebra

March 25, 2011 - 9:33 am

Knitting requires math.  Whether I solve a problem physically by separating stitches onto multiple needles or with markers, or on paper, math is getting done.  And math doesn’t have to be scary; particularly not knitting math where you have the object in question in your hand and can check your answer to make sure you got it right!

Today I am working on a pattern for a toe-up sock.  I want it to be 60 stitches around.  I have cast-on 24 sts and dutifully increased 4 sts every other row to get to my desired stitch count, worked the first row of the instep chart, and discovered a problem.  The chart is 29 sts across, so I need to add a stitch.

Looking at the chart, the best way to do this is to add an m1 to the last instep increase round.  On the needles I can fudge this easily enough by finding the middle two stitches and nudging them apart so I can create an increase a couple rows below.  I hate ripping, and avoid it wherever possible, trusting blocking to find me the slack for those extra stitches.

For my directions, however, I’d like the knitter to be able to put the increase in the way they should,  which means I need to figure out how many stitches they need to knit on either side of the centered increase.  Perhaps I haven’t had enough tea this morning, but I needed to resort to pen & paper for this exercise:

I’m a bit handwriting challenged, so let me translate for you.  I know I need the top of the foot to look like this:

P1, m1, k?, m1, k?, m1, p1.

I need that to add up to 31, which means I need to solve this:

2 + n + 1 + n + 2 = 31 sts

which is the same as:

2n + 5 = 31

which I can shuffle around to be:

n = (31 –  5)/2

telling me I need 13 sts between the m1’s, for a knitting row of:

P1, m1, k13, m1, k13, m1, p1.

That adds up to 31 sts!  Yay for math!

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