The slide rule was the predecessor to the calculator. My mother worked for Texas Instruments in Fort Worth when the first handheld calculator was created in 1967, so we were some of the first kids to be using them.
I hated math, but excelled in Science, Geography and English. I also loved taking things apart to see how they worked, and could usually put them back together. I did that with a frog once, formaldehyde to put him to sleep, looked around inside, sewed him up, but he never woke up and got a special funeral, my sister attended.