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

X-height

In typography, the x-height or corpus size refers to the distance between the baseline and the mean line in a typeface. Typically, this is the height of the letter x in the font , as well as the u, v, w, and z...

; 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

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 presses have been partial to "old-style" numerals, even though typewriter

Typewriter

A typewriter is a mechanical or electromechanical device with keys that, when pressed, cause characters to be printed on a medium, usually paper. Typically one character is printed per keypress, and the machine prints the characters by making ink impressions of type elements similar to the pieces...

s cannot print them and they are not (yet) assigned corresponding Unicode

Unicode

Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

 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

Fokker D.VII

The Fokker D.VII was a German World War I fighter aircraft designed by Reinhold Platz of the Fokker-Flugzeugwerke. Germany produced around 3,300 D.VII aircraft in the summer and autumn of 1918. In service, the D.VII quickly proved itself to be a formidable aircraft...

, Ki-84-III, and Spitfire Mk I

Supermarine Spitfire

The Supermarine Spitfire is a British single-seat fighter aircraft that was used by the Royal Air Force and many other Allied countries throughout the Second World War. The Spitfire continued to be used as a front line fighter and in secondary roles into the 1950s...

) almost to the end of World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. A policy of the Labour

Labour Party (UK)

The Labour Party is a centre-left democratic socialist party in the United Kingdom. It surpassed the Liberal Party in general elections during the early 1920s, forming minority governments under Ramsay MacDonald in 1924 and 1929-1931. The party was in a wartime coalition from 1940 to 1945, after...

 Government of 1945 discontinued their use, although they continue to be used in the U.S. and Germany (e.g., Douglas D-558-II

Douglas Skyrocket

The Douglas D-558-2 Skyrocket was a rocket and jet-powered supersonic research aircraft built by the Douglas Aircraft Company for the United States Navy...

, Saturn V

Saturn V

The Saturn V was an American human-rated expendable rocket used by NASA's Apollo and Skylab programs from 1967 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload...

). 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

Computer program

A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...

, which aren't going to be intercorrelated.

Slashed zero

A distinction exists between the Danish

Danish language

Danish is a North Germanic language spoken by around six million people, principally in the country of Denmark. It is also spoken by 50,000 Germans of Danish ethnicity in the northern parts of Schleswig-Holstein, Germany, where it holds the status of minority language...

/Norwegian

Norwegian language

Norwegian is a North Germanic language spoken primarily in Norway, where it is the official language. Together with Swedish and Danish, Norwegian forms a continuum of more or less mutually intelligible local and regional variants .These Scandinavian languages together with the Faroese language...

 letter "Ø

Ø

Ø — minuscule: "ø", is a vowel and a letter used in the Danish, Faroese, Norwegian and Southern Sami languages.It's mostly used as a representation of mid front rounded vowels, such as ø œ, except for Southern Sami where it's used as an [oe] diphtong.The name of this letter is the same as the sound...

," the Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 letter "O," and the numeral "0".
Handwritten data to be typed into a computer necessitates having a distinction between the oh and the zero. In English-speaking countries, zero

0 (number)

0 is both a numberand the numerical digit used to represent that number in numerals.It fulfills a central role in mathematics as the additive identity of the integers, real numbers, and many other algebraic structures. As a digit, 0 is used as a placeholder in place value systems...

 was often slashed in technical writing, and was used in many computer keyboard

Computer keyboard

In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches...

s, screens, and printing methods. Some early computerized systems for managers assumed that the numeral would be entered more often than the letter, so they slashed the oh instead. In time this became a minority practice, and it is very confusing for Danish and Norwegian speaking people.

There are three ways of ticking the numeral zero to make it distinct from the letters O and Ø. A tick in the upper right corner derives from the earlier practice, a tick in the upper left corner is used to prevent confusion with all earlier practices, and the very-low-resolution typeface

Typeface

In typography, a typeface is the artistic representation or interpretation of characters; it is the way the type looks. Each type is designed and there are thousands of different typefaces in existence, with new ones being developed constantly....

 "Fixedsys

Fixedsys

Fixedsys is a family of raster monospaced fonts. The name means fixed system, although it is often pronounced "fixed size" because its glyphs are monospace or fixed-width...

" has an internal tick, that does not extend beyond the bowl, in both the upper right and lower left. This is the most elegant, but it would take quite a flourish to write it on hundreds of inventory tags. Scandinavian countries prefer a numeral zero with a dot in the middle, although low-resolution displays can confuse this with a numeral eight, and it takes longer to assuredly make a dot with a ballpoint pen than making a tick.

Other variations

The "Crossed Seven" is commonly used throughout Europe, but is sporadically used in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, and it is not permitted to be written on some inventory tags that are optically read by computers. This modification of the number seven is caused by the numeral one with a long initial stroke and no underserif. There are two more forms of the numeral seven used in France, as seen on Citroën cowls:

• numeral one with a long initial stroke and an underserif; and
• numeral one with a long initial stroke that starts below the underserif and is concave upward.

The Germans have used a numeral one that has two half-serifs so it looks somewhat like a 'Z

Z

Z is the twenty-sixth and final letter of the basic modern Latin alphabet.-Name and pronunciation:In most dialects of English, the letter's name is zed , reflecting its derivation from the Greek zeta but in American English, its name is zee , deriving from a late 17th century English dialectal...

'. The Germans use a numeral four that looks like a lightning bolt, and in some areas of Eastern Europe, as seen on Romania

Romania

Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

n tanks, there is a numeral four that does not have a closed loop, but has a Greek cross form of strokes. Usually the numeral two is not slashed, whereas the letter Z is, because handwritten form could be confused with the numeral two.