The profile picture is quite a give away 
I’m old enough to have longed in my early youth for a slide rule so much that I built several using cardboard and log tables.
Considering I was about 10, the results were quite decent.
I got my first when my mechanical engineer grandpa died ( 
), but by that time I already had a battery devouring TI-30 and also a Sinclair kit contraption (I love RPN, and still do use my DM42 every day…).
Pfft. For about 10-12$ you can get 150F. 
