I'm glad I'm not the only one who puts things down then immediately forgets where....
Me, some years ago now, and and before I owned a computer that holds a calculator.:
Awkard calculation for a hobby project, perhaps a difficult square-root or something like that; but anyway too hard for pen-and-paper.
Scientific calculator - I could not find it anywhere.
Errr... slide-rule. That was hiding as well, likely sulking because the calculator had displaced it.
Nothing for it: Logarithms. The pre-calculator necessity. Found a text-book with the appropriate tables, and used the example given for a little preliminary revision, though they are simple to use*. Successfully completed the calculation.
Next day: Bought new calculator. I was surprised to find that although portable telephones had shrunk almost to sensible shirt-pocket size, calculators had all expanded from pocket-size to roughly what would become "smart"-'phone size, but thicker.
Three weeks later: Searching for something else, opened a drawer, only to find the household gremlins had put the AWOL sum-box in there. I knew I hadn't put it there, of course...
+++++
*Half of the Number's base-10 logarithm, read from the table, = the log. of the Number's square-root; the antilog. of that is the root itself. Not something I do regularly, but I can still remember the technique!
