An interesting byproduct of using the A series of paper is that when you work with maps that are printed on such paper, the scales of the maps are easy to convert when changing paper sizes.
Say, for example, you have a map printed on A1 paper and the map is at a scale of 1:1,000. If you want to print the map on smaller paper, because of the ratio of the paper sizes, you can drop the paper two sizes (to A3) and the scale will reduce to 1:2,000.
Likewise, if you have a map printed on A4 paper and the scale of the map is 1:50,000 and you want to print the map at a scale of 1:25,000, you can print it on A2 paper.
Say, for example, you have a map printed on A1 paper and the map is at a scale of 1:1,000. If you want to print the map on smaller paper, because of the ratio of the paper sizes, you can drop the paper two sizes (to A3) and the scale will reduce to 1:2,000.
Likewise, if you have a map printed on A4 paper and the scale of the map is 1:50,000 and you want to print the map at a scale of 1:25,000, you can print it on A2 paper.
