I usually try doing it in my head first. I use paper if it is available. I use a calculator when I don't have time, or fail at the first two steps.
I noticed my number skills were deteriorating without proper use, and I found that alarming. I'm still weaker than I used to be, but not as bad as I was.
It's just important to think for ones self when one can. The brain is a muscle that atrophies without use.
Met the love of my life on plenty of fish. Never been happier than these last ten years. 50 now.
It's not easy finding a decent woman on there though, won't lie, I struck gold.