A random shot of my calculator 5000 miles from home while I enjoy a beer near the Pacific. We had been discussing how much water was on earth and what size of a ball it would make. I have no affiliation with the brewing company so apologies for the product placement.
Yes, in fact before I got my DM42 I had one holiday where we had no internet access in the evenings and as the children were small and slept early, I didn't have much to do but I was able to learn a lot about using and programming free42.