Remember this?
The hottest tech gadget in the summer of 1975. The boomers’ iPhone!
The inflation adjusted cost today? $1,600.98! How’s that stack up with a modern day laptop or tablet at $500-1,000?
This ad from the June 1975 Technology Review goes a long way in explaining the productivity boom of the past thirty years. Enjoy your technology and keep it in perspective, comrades! (click here if ad is not observable)
Global Macro Monitor 
I remember. The HP series, starting with the HP-35, put slide rule makers out of business. Creative destruction and all that.
I have a Scientific calculator purchased in 1985 made by Casio, model fx-570MS. It has never needed a new battery and works just fine.
In May 1975, in my senior year of college, I showed up for my final exam in Microelectronics with my trusty K+E Deci-Lon slide rule. When the professor saw it, he said I would not be able to complete the test with a slide rule, and loaned me his brand new HP-55. Few students owned calculators, but there had been a lot of borrowing during exams. $395 was about two semesters worth of books, or one semester of room and board.
The last time I used a slide rule “for real” was around 1996 – with two dead calculators, someone pulled a slide rule out as a joke, but didn’t know how to use it. I demonstrated how it worked to a bunch of amazed people.