Casio
Early on, Casio was dismissed as cheap Japanese stuff. For years after WWII, "Made in Japan" meant low quality. But Japan came back big time and made wide inroads in the all-American industries of cars and electronics.
Casio fx-58
This was the 3rd calculator I owned, bought around 1980. It was amazing for the time.
The size of a credit card, it featured scientific calculations, a timer, a clock, 2 alarms and a stopwatch! The only problem was, using any of the time features ate up the battery within a couple days! It came with a leather pouch and a reference card of physical constants and conversions.
Alas, it doesn't work anymore, the batteries having leaked and infiltrated the LCD display.
Casio M-810 "micro mini"
A jewel, measuring only 2.4" x 1.75" (but kinda thick at 0.54") I think it was a demonstration of Casio's ability to make things smaller more than an effort to make a useful calculator.
This unit is pretty much mint.
Casio fx-17
A very cleanly designed handful. The display uses half-sized zeros.
Casio AL-8
The first handheld to do fractions!
A strange, idiosyncratic beast that strikes me as too awkward to use seriously. But maybe it just takes getting used to.
Of particular concern there is no interplay between the modes. For instance if you're in GT mode and accumulating a grand total, switching to square-root mode will lose it.
Second, even though fraction mode and sexigesimal mode involve entering and calculating 3-part values, they work utterly differently.
But the calculator looks great with the odd choice of a burgandy color for the surround and memory keys making it distinctive. It works well and feels good in your hand.
The calculator has switches for 3 display and 6 function modes.
The display offers floating point, and two 2 decimal modes: CUT (truncate) and 5/4 (round).
The function modes determine the behavior of the P button.
1. As a square root key
2. As a grand total (GT) key (recall a memory that gets incremented by the result every time the = key is pressed.)
3. In "rem" mode, the calculator does integer division and P returns the integer remainder.
4. Use "a b/c" to put the calculator in fraction mode, and press P to enter the parts of a fraction. E.g. four and on-third is entered as 4 P 1 P 3. Each P-press is represented in the display by the hook delimiter.
After entry, you can press = to reduce the fraction to its simplest form. Or you can press any function key. Results are shows as fractions, but you can press P at any time to convert a result to a decimal.
Amazingly, Casio didn't provide a way to convert decimals back to fractions.
5. The "hms" setting puts the calculator in sexigesimal - base 60 - to work with angles in degrees-minutes-seconds, or time in hours-minutes-seconds.
You press P between the parts of a time/angle expression, but unlike fraction mode, it doesn't place the "degree" delimiter in the the display. Instead it accumulates the part into the display as a decimal number. I.e. pressing 1 P 30 P produces "1.5" in the display. You're effectively working in decimals all the time, until you press =.
After that, if you press P, the decimal just calculated will be displayed in sexigesimal. The above display is from these keystrokes (taken from the manual):
1 P 23 P 45 P + 6 P 54 P 32 P = P
6. In SD (standard deviation) mode, you repeatedly type a value and press = to enter it as a point to a data set. When you're done entering points, you can press P to get their standard deviation. You can also use the memory keys to get other statistical information: the average (M+), the number of points (M-), the sum of the squares (MR) and the sum of the points (MC).
Casio Biolator
Biorhythms are one of the nuttier crazes I've lived through, but there was a moment back in the '70s where people were drinking this up. There were supposedly 3 cycles, of different lengths, that began the moment you were born. The Physical wave, governing your body, crested every 23 days. The Sensitivity wave, governing your emotions, peaked every 28 days. The Intellecual wave, governing your reasoning capacity, had a wavelength of 33 days. So, on any given day you were at various different phases of each wave and thus susceptible to a mix of influences that this little baby would help you track. Hey, it has to be scientific if it's in a calculator, for sure!
Casio Minis
Casio had a whole bunch of calculators in the Mini line. In spite of the name, the machines were hardly small even by the standards of the day.
They were characterized by "shifting" displays and half-height zeroes. lol.
There's a fun bug in these calculators: divide by zero and the display will fill appropriately with zeroes to indicate the overflow. But then press the shift key to see a timer counting up!
In all these calculators, the - sign took up a position. It was usually displayed on the left of the unshifted display, but if a negative result had more than 6 significant digits it would be get moved to the right of the shifted display. Just plain nutty - unless you were keeping mental track, you always had to press "shift" to be certain of the sign of your result!
The CM-604 version only had a 6 digit display, in which it would show the most significant 6 digits of any calculation. If a result had more digits, you held the "shift" button (next to =) to see them.
Multiplication could yield up to 12 significant digits, but division only produced 6, excepting leading 0s.
But entered values were limited to 6 digits, and so were results carried into chain calculations! Guess it wasn't intended for people interested in millions.
A nice feature is automatic constants: doing A op B = results in B as a constant for whatever operation "op" is (+, -, x, /). So 2 x 3 = 4 = yields 12. This gives a ways to turn a result negative: enter - = = after generating it.
Note from the size of the wrist strap how big this really is, over 6 inches long, 3 inches high and 1 1/4 inches thick.
By moving keys around a bit, the CM-605 version was made a little slimmer, vertically. This one has, sadly, died.
The Mini Memory added a Total mode to the power switch. In this mode, every time you press =, the calculated result is added to a Total memory. If you want to want to subtract a result from the memory, you use the RED equal sign in the top row. You press the T key to display the accumulated Total.
Note that you could switch out of Total mode to do calculations without affecting the Total. When you switched back in, the Total would be recalled.
This version had 8 digits, but kept the shift key anyway.
It featured automatic constants for x and /, but oddly not for + and -. So unlike the 604, there's no way to turn a positive result negative. It's therefore a good thing the red = key is there for totaling.
Casio 8R
Apparently a follow-on to the Minis, it dropped about 20% of the size along with the shifty display (rah!).
It kept the strange behavior of the Mini Memory's Total mode (without a non-Total mode) but lost a way to subtract a positive result.
The 8R shares an odd feature for NON-automatic constants with the A8: A op op B = makes A a constant for op.
So 2 x x 3 = 4 = yields 8.
But it only works when op is x or /. Since it can't be used with -, there's no way to turn a positive result negative.
Casio fx-8000G
A double handful of graphing and programming power. Just jam-packed with functions! And it boasts a port to connect it to a printer/cassette unit.
Casio fx-7700G
Another graphing calculator, somewhat simpler but with a great feel.
Casio ML-831
It's musical! Slide the switch to the position between OFF and CAL, and the keys sounds the tones of an octave as you press them. I suppose this could have helped amuse you between calculations.
