The mathematician in me

Recently there was a program on the ABC called the Story of 1. It was a history of mathematics from the first marks made to count items through to the realisation than there should be a number for nothing ie zero and the introduction of binary numbers used extensively in computing. There were some very interesting facts in the program such as while the Romans were using numbers to organise their armies into centuries. (100 men led by a Centurian) the Indians were using numbers to determine the area of land that they needed to sow to enable sufficient crops to be produced to meet their needs – I know which civilisation I would have preferred to be living in. Anyway how does all this relate to knitting?

  • How many stitches do I need to get the right size?
  • Do I have enough yarn to make it?
  • If I use all the yarn how big will it be?
  • If I change the gauge how will the final size change?

The reason the questions came to mind was that the garter stitch wrap I am making requires 3000 yds of yarn. It is a square shawl made from 4 identical right angle triangles. I have 2000 metres but I’m knitting it at a larger gauge. So how big will it be? Is it worth continuing? Of course if I had swatched, blocked the swatch and measured it I could have done this before starting. I have found however that I can’t gauge the drape of a fabric in a 10cm square and the bigger the sample the more accurate the answer. (I was also taught from a very young age that swatching is a complete waste of time – Thanks Mum.)

I have knitted 2 balls (200m) and I have a right angle triangle that is 15″ from the point to the centre of the opposite side.

This means I have an area knitted that is 15×15=225 square inches. So for 5 balls I will be able to make 225 x 5/2 = 562 sq in.

This will give me a triangle with a height of 23″.

There are 4 triangles making a square in the design so the width and length of the finished wrap pre blocking will be 46″.

Blocking should add 10% so I should end up with a square of almost 51″ if I use all the wool I have.

The pattern is for a square that is 55″ along each edge so I will end up with a wrap that is almost as big as the original pattern. As I am only 5’2″ and slim this will be fine.

So I now know what the finished dimensions will be after completing 10% of the project and that it is worth continuing.


2 thoughts on “The mathematician in me

  1. Even with out a proper zero, the egyptians used a form of binary –divide by 2, and cast out remainders.

    I love math.. and its such a wonderful simple tool… (simple enough to learn the basics before the age of 5 (most preschoolers learn to count!) engaging enough to last a life time!

    (knitting –with its basic k & P is very binary..

    cables mimic assembly language multiplication!

  2. All I can say is thank goodness for patterns. Even though I like Maths. I don’t appreciate it that much.

    That is why I NEVER knit without a pattern.

    PS. I don’t swatch either. Waste of time and yarn.

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