Spreadsheet Page Blog
Calculating In The Pre-Excel Days
This is an interesting site: Retro Calculators.
Here's a device called the Add-A-Mite Pocket Calculator ("Handsome as jewelry, accurate as a watch").
This simple mechanical pocket adder is made of aluminum with bright blue paint and dates perhaps from the 1950s. The cursor on the right is depressed and dragged to the number you wish to add, 0 to 99. When released, the cursor engages a gear tooth on the back of the disc and when you then drag the cursor clockwise back to the 0 position, your number is added to the result. Crossing from 99 to 00 causes an automatic carry into the hundreds window, allowing sums up to 2,499. Subtraction works similarly by starting from zero and dragging counter clockwise to the desired number.
Back then, people rarely added numbers that exceeded 2,499.
Sadly, version 2 failed miserably in the marketplace. The world just wasn't ready for Add-A-Mite-With-Pivot-Tables.