ADAMSATOR

About the Addiator

Before electronic calculators, pocket slide adders used numbered metal strips and a stylus. The Addiator, introduced in Germany in 1920, was a well-known example. Each strip represented a decimal place; windows above showed the total. The Adamsator works the same way using touch.

Addition

Choose Addition. Each numbered tooth adds its value to the corresponding column. The colour tells you which way to slide: cream down, red up. The callout bubble shows the chosen number in the same colour, with an arrow for the direction.

Entering 99,895

Start with a cleared display. In the rightmost (units) column, touch the small tooth beside 5. The bubble shows a cream 5 with a downward arrow. It is cream, so keep your finger on the screen and slide down to the end of the track, then release. The units window changes from 0 to 5.

Work right to left: select 9 in tens, 8 in hundreds, 9 in thousands and 9 in ten thousands. Each is cream, so slide down. The display now shows 99,895.

Worked example: add 213

1. Units: add 3

Select 3 in units. It is cream, so slide down. The units change from 5 to 8.

Result: 99,898

2. Tens: add 1

Select 1 in tens. It is red because 9 + 1 needs a carry, so slide up. The tens become 0 and the hundreds increase from 8 to 9.

Result: 99,908

Why red? Each column holds one digit. A red movement wraps that digit back below 10 while carrying 1 left. On a mechanical Addiator, the hooked track guided the stylus through the carry. Here the hook is optional: sliding to the far end is sufficient.

3. Hundreds: add 2

Select 2 in hundreds. It is red, so slide up. The hundreds become 1, but the carry reaches a 9 in the thousands, producing an upward arrow.

Select 0 in thousands and slide up. Another arrow appears in ten thousands; select 0 there and slide up again.

Final result: 100,108

For each upward arrow, select 0 in that column and slide up until all carries are complete.

Clearing and Undo

Pull the silver bar upwards to clear. You do not need to clear between additions.

Undo reverses one completed action at a time, including clearing and setting a starting number. Up to 100 actions can be undone in the current session.

Subtraction

To switch to subtraction, tap the Addition/Subtraction toggle button beneath the sliders. When it shows − SUBTRACTION −, subtraction is selected. The displayed total is kept, so you can subtract directly from an addition result.

Directions reverse: cream up (no borrow), red down (borrow required). Borrowing takes 1 from the next column to the left, reversing the carrying process. For a downward arrow, select 0 in that column and slide down. Repeat until the arrows disappear.

Setting a starting number

To subtract from a new number, choose Set starting number. This replaces the existing result. Enter the number using normal addition movements, then choose Done · subtract. There is no need to clear first.

The Adamsator handles non-negative whole numbers from 0–999,999. Out-of-range results are flagged; use Undo or clear.