|the casio al-10 is a personal favourite of mine.
from 1976, it displays 10 digits and is very easy to use with large buttons that
are easy to press.
together with the 4 basic functions and a memory is a rather splendid mechanical
six position switch which defines the function of the top right 'p'
button. these functions are:
- square root
- grant total
- hours, minutes & second
- statistics (standard deviation)
a lot of these operate as modes rather than pure function. for example,
GT tallies the total sum for every '=' and
is recalled by pressing 'p', rem puts the
machine into a remainder mode where only the integer part is displayed
after a division and the remainder can be recalled by pressing 'p'.
although the al-8 was the first fractional
calculator, the al-10 fraction mode is more useful because of the 10 digit
display. the whole part, the numerator and the denominator each cannot
exceed three digits and the total cannot exceed 8 (eg 1234½ is not
allowed). for example 355/226 is reduced and correctly displayed as
1/129/226 whereas this cannot be accommodated on the al-8.
the other switch alters the rounding mode for normal floating point
operation. the choices are cut, which
truncates to 2 decimal places or 5/4 for rounding.
internally, the machine operates to 10 digits with no guard.
this model would suffer the sticky button