I'm that old, too. Can you imagine a student back then saying, "I'll have a calculator, flashlight, camera, video recorder, music collection, and games to pass the times I have to wait on others."
"Oh yeah and it's also a computer that's more powerful than any computer you've ever laid eyes on that has access to an unimaginable wealth of human knowledge via a wireless connection to the Internet."
This wasn't all that long ago though. I'm only in my 30's and was told this in elementary school in the 90's and early 2000's. The iPhone was first released only 16 years ago.
Yes really, if your job requires lots of calculations you'd be stupid not to have one, even back when they were expensive.
Every machinist I know, even the crusty old ones, carry a calculator in their pocket. It's indispensable. Why wouldn't you carry one if you need it all the time?
And yet my point stands: if you need to do a lot of calculations at your job, you'd be stupid not to have a calculator in your pocket. And if you don't, then the time it takes to find a calculator will be negligible.