This section includes animated displays of computation using the Iconic Calculator. Each of the three modes shows a different number system. All use depth-value notation implemented as 2D container numbers. The * Image* is of the GOM department store, the largest store in Moscow, in 1956. The clerk is calculating a customer’s bill using a large abacus, apparently the state of the art in cash registers at the time.

## Section Contents

The * Iconic Calculator* shows dynamic animations of iconic computation in three modes: binary, decimal using discrete units, and decimal using numerals.

The * Binary Calculator* shows the addition and subtraction of binary numbers .

The * Decimal Unit Calculator* shows the addition and subtraction of decimal unit numbers.

The * Decimal Digit Calculator* shows the addition and subtraction of decimal digit numbers. This calculator closely resembles our current arithmetic system, except that it uses spatial/iconic rather than linear/textual principles of computation.

The first animation on each page shows the entire sequence of entering a problem and computing the solution. The rest of the animations show only the Iconic Arithmetic Calculator display screen while suppressing the keyboard and video controls.