Prior to the age of microcomputers was the parade of pocket calculators. These little wonders enabled algebra, statistics, and even algorithms to be explored at very low cost. It was a time of tremendous empowerment. Numeracy blossomed in schools and homes.
Some of the calculators I've worked with:
AGS 14
I got one of these as a gift when I was in high school in the mid 1970s. Endlessly fascinating, almost magical. Voracious power hog though (batteries had to be replaced frequently, perhaps due to over-use)
TI-30
The workhorse of many a high schooler in the 1970s. This was the original model, many upgrades would follow. It added lots of scientific, statistical, and memory functionality. Pre-installed algorithms and tables were packed into this little beauty at a very low cost. It had a nice bounce-less keypad and was power efficient.
Commodore PR-100
For a budding computer programmer readying for university, this was a game-changer. My first programmable calculator. It sported 72 step keystroke storage (but program was lost when powered off). This allowed simple algorithms to be entered and ‘replayed’. I wrote such algorithms down in a notebook, and entered them as needed. Such programmable calculators were strictly verboten on tests, but still allowed me to explore simple ‘automation of thought’ for the first time. Halcyon days.
TI-59
In university, it was time for a serious calculator. This was top-of-the-line and ultra powerful. It featured magnetic program storage strips, with a motorized internal card writer/reader. Also tiny ROM modules that had suites of application-specific programs. Also an optional thermal printer. The only thing lacking was an AI library, so I wrote my own programs. Too expensive by far, but I had no other vices, so I could just barely afford it.
HP-41CV
The alphanumeric display on this model allowed for simple yet readable text processing, very handy for AI apps such as Expert Systems. Also, the RPN entry system is the same as in FORTH, my favourite language, so it was already familiar and useful.
TI-83+
This model had features like a large screen, good alphanumerics, a powerful graphing facility, and a Z80 CPU. It was also possible to network with other TI-83s and computers. This enabled it to participate in NetLogo agent-based simulations.