European paper sizes are magical! Over the years we have done a lot of work with folding paper, to teach Maths, We once went to a maths conference and, between sessions, I got into conversation with an American man and we got to talking about European paper, as you do! He knew almost nothing except that the most commonly used size is called A4. I explained that joining two A4 sheets creates A3, which is exactly the same shape as the starting shape but with twice the area. Two A3 give A2; two A2 give A1; two A1 give A0; A0 is a rectangle, of the same shape, with an area of one square metre. One of the practical advantages of metric paper sizing is that fewer envelope sizes are needed. Any size of paper can be folded in half, half again, etc. to fit in any envelope. By one of those strange coincidences that sometimes happen, we proceeded to the next
session and, at the door, we were each given an A4 sheet of paper, with some sort
of symbol to find a group to join. Each group was given instructions about folding
the paper and assembling it the group’s sheets in a particular way. The climax of
this warm The American started jumping up and down, like a five This system of sizing works because multiplying the length of the shorter side by
the square root of two (approximately 1.4) gives the length of the longer side. Multiplying
the longer side by half of root two (approximately 0.7) gives the length of the
shorter side. These numbers might not appear to make sense but it is all down to
the special properties of root 2 and its reciprocal. This was the same property we
had been using for many years to create our 45 The one square metre size is usually referred to as ‘A Nought’. We have corrupted
the title so you might think of it by its proper name or as Ay The afghan is knitted using the log cabin technique so is very easy to make using only one yarn at a time.  

Size 
Width in mm 
Height in mm 
Area in sq m 


A0 
841 
1189 
1 


A1 
594 
841 
1/2 


A2 
420 
594 
1/4 


A3 
297 
420 
1/8 


A4 
210 
297 
1/16 


A5 
148 
210 
1/32 


A6 
105 
148 
1/64 


A7 
74 
105 
1/128 


A8 
52 
74 
1/256 


A9 
37 
52 
1/512 


These numbers have been rounded 
