Arabic Numeral Variations - Old-style Numerals

Old-style Numerals

The numerals used by Western countries have two forms: lining ("in-line" or "full-height") figures as seen on a typewriter and taught in North America, and old-style figures, in which numerals 0, 1, and 2 are at x-height; numerals 6 and 8 have bowls within x-height, and ascenders; numerals 3, 5, 7, and 9 have descenders from x-height; and the numeral 4 rests along the baseline.

British presses have been partial to "old-style" numerals, even though typewriters cannot print them and they are not (yet) assigned corresponding Unicode values. This has led to confusion, as the old-style numeral one can resemble a capital "I" reduced to x-height. In the U.S., a typewritten "I" refers to Roman numeral one; during the typewriter age, the minuscule "l" was first used for it, before the separate numeral character "1" was added to keyboards. A prime example of this confusion is the case of a British typist sending a letter to an editor, as seen in the periodical Spaceflight, about the space flight "Apollo II," for which the reading "Apollo Eleven" would be intended, whereas this would be read by Americans as being Roman numerals, as a non-existent "Apollo the Second."

British use of Roman numerals declined during the 20th century, having previously been used for aircraft (e.g., Fokker D.VII, Ki-84-III, and Spitfire Mk I) almost to the end of World War II. A policy of the Labour Government of 1945 discontinued their use, although they continue to be used in the U.S. and Germany (e.g., Douglas D-558-II, Saturn V). They are still used in complex outlines, in which the structure of relations is necessary to be memorized, rather than simple mods of a computer program, which aren't going to be intercorrelated.