the casio al-8 is a handy little machine for
quick and easy calculation. it was the first calculator to support
fractions and released in 1976. it was quickly superseded by the al-10
which is the same but with a ten digit display.
although fractions was an exciting new feature, the 8 digit display was
a major limitation with this machine. fractions are represented using a
separator symbol which takes up one digit position. thus only 6 digits are
available to display a fraction when a whole part is included. so for
example, the number 355/226 cannot be displayed, because once reduced
becomes 1/129/226 which requires 9 digits.

i often wonder why casio did not choose to use the decimal point symbol
to delimit the fractional parts. each digit of the display can display a
dot as well as the 7 number segments. the above example would then display
as, 1.129.226. pure fractions would show a zero whole part, eg 0.1.2 for
1/2 otherwise they might be confused with floating point numbers.