Math Monday: Increasing - Part I - along the length

A few Mondays ago, I discussed decreasing along the length of knitted fabric, and we did the calculations. Today, we’re going to do the same thing for increasing. You can read that here (in fact it might be useful if you did before you begin reading this one.)

The sleeve of Ledbetter is worked from cuff to underarm with a modified drop shoulder shaping to eliminate bulk at the underarm.

This works the exact same way, so let’s review using a new sweater that I’ll be publishing in the late summer/early fall, Ledbetter. Ledbetter’s sleeves are worked in the round from the cuff to the upper arm and then seamed onto the body. The sleeve is mostly worked in Stockinette stitch but it starts with a bit of the textured pattern - 1.5” [4cm]. The length of the entire sleeve with the cuff is 16.5” [42cm], but I’ll only be doing the increasing over the stockinette portion of the sleeve, not the cuff. That’s 15” [38cm].. As I wrote when we discussed decreasing, it’s never a good idea to immediately begin decreasing or increasing on the first row/round, and it’s never good to end them on the last row/round either. I usually begin and end with 1” [2.5cm] at the beginning and end worked even.

So, if we take out the 1.5” for the cuff and the 1” at the top and bottom the sleeve (2” total), we are left with 13” (16.5 - 1.5 - 2 = 13”). At a Stockinette row gauge of 6.75 rounds per inch, that leaves us with approximately 88 rounds with which to work {13 x 6.75 = 87.75 - I always round to the nearest even number}.

For Size 2, the cuff begins with 40 sts (9” x 4.25 sts/inch - rounded to the nearest 4 sts) and the upper arm ends with 60 sts (15” x 4 sts/inch), which means I need to increase 20 sts. Remember, these stitches are worked in sets - one at the beginning of the round, one at the end of the round. I’ll need 10 sets of 2 stitches each totaling 20 sts. However, I’ll do the very first set on the very first round since I’ve already left 1” before I’ve started the decreases I won’t need to leave more. This now brings the total down to 9 sets of decreases over 87 rounds.

I do the math just like I did for decreasing:

With this set up, you can see that you’ll have to do a increase every 9th round 3 times and every 10th round 6 times. You can decide how you’d like to set this up - you could do it as it’s laid out or you could do *every 10th round 2 times and then every 9th round once and then repeat from * twice more. All your increases will be evenly placed along that sleeve!

Of course, if you want to shorten or lengthen your sleeve, with this formula, it’s easy to do. You’ll still need the same number of increase sets (your divisor), but your dividend will change. You can use math to evenly space out your increases every time.

And this has other uses besides sleeves. You can add body shaping (waist to bust shaping (bottom up) or bust to waist (top down). for example. Or you can use this to modify a front or back neck depth or adjust an armhole.

A few thoughts before we finish…

• Just like with decreasing, increases should never be placed at the very beginning or end of the row or the round. If you’re working in rows, it will be difficult to seam. If you’re working in rounds, the stitches will be distorted at the “seam line.” I usually place mine 2 stitches after the start of the row/round and 2 stitches before I end the row/round.

• Another hint to make your knits aesthetically pleasing is to be sure your increases “lean” the way your sweater is growing. For example, in this sweater, the sleeve is being worked from the cuff up to the underarm, growing in circumference. Therefore, the increases at the beginning of the round should lean left and the ones at the end should lean right.

Using math to make adjustments to your knitting in this way will help you customize your garments for a more perfect fit.