Display of fractional
numbers is controlled by the d o
(calc-over-notation) command. By default, a number
like eight thirds is displayed in the form
‘8:3’. The
d o command prompts for a one- or two-character
format. If you give one character, that character is used as the
fraction separator. Common separators are
‘:’ and
‘/’. (During
input of numbers, the : key must be used regardless of
the display format; in particular, the / is used for
RPN-style division, not for entering fractions.)
If you give two characters, fractions use “integer-plus-fractional-part” notation. For example, the format ‘+/’ would display eight thirds as ‘2+2/3’. If two colons are present in a number being entered, the number is interpreted in this form (so that the entries 2:2:3 and 8:3 are equivalent).
It is also possible to follow the one- or two-character format with a number. For example: ‘:10’ or ‘+/3’. In this case, Calc adjusts all fractions that are displayed to have the specified denominator, if possible. Otherwise it adjusts the denominator to be a multiple of the specified value. For example, in ‘:6’ mode the fraction ‘1:6’ will be unaffected, but ‘2:3’ will be displayed as ‘4:6’, ‘1:2’ will be displayed as ‘3:6’, and ‘1:8’ will be displayed as ‘3:24’. Integers are also affected by this mode: 3 is displayed as ‘18:6’. Note that the format ‘:1’ writes fractions the same as ‘:’, but it writes integers as ‘n:1’.
The fraction format does not affect the way fractions or integers are stored, only the way they appear on the screen. The fraction format never affects floats.