casio al-10

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
  • remainder
  • fractions
  • 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 1234 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.

sometimes this model would suffer the sticky button problem.