Calculator input methods

There are various ways in which calculators interpret keystrokes. These can be categorized into two main types:

On a single-step or immediate-execution calculator, the user presses a key for each operation, calculating all the intermediate results, before the final value is shown.
On an expression or formula calculator, one types in an expression and then presses a key, such as "=" or "Enter", to evaluate the expression. There are various systems for typing in an expression, as described below.

Immediate execution

thumb|upright|The [[TI-108 is a simple four-function calculator which uses single-step execution.]]

The immediate execution mode of operation (also known as single-step, algebraic entry system (AES) Casio calls this method the Visually Perfect Algebraic Method (V.P.A.M.), and Texas Instruments calls it the Equation Operating System (EOS). or not.

Ten key notation

thumb|This printing calculator made by Sharp uses ten-key notation. Notice the size and placement of the keys, including the extra-large "+/=" and the red "-/=" keys.

The ten-key notation input method first became popular with accountants' paper tape adding machines. It generally makes the assumption that entered numbers are being summed, although other operations are supported. Each number entered is followed by its sign (+/−), and a running total is kept. An assumption is made that the last operand can be implicitly used next, so by just entering another + (for example), one will reuse the most recent operand. Ten key input mode is available in printing calculators from companies such as Sharp, and in software calculators like Judy's TenKey used by accounting firms. Online tenkey training and certification tools are available as well, and some businesses use ten key typing speed as an employment criterion.

{| class="wikitable" border="1"

|+ Examples

! Formula

! keystrokes

! keystroke count

| <math>1 + 2 \times 3</math>

| 8

| <math>\sin 30 \times \cos 30</math>

| 8

| <math>5-3</math>

| 5

| <math>15+10+10+10</math>

| 9

Mathematical display

thumb|200x200px|A Casio Natural Display scientific calculator displaying mixed fractions and their decimal equivalents in pretty-printing

left|thumb|Pretty-printed commands used to plot [[Dini's surface in Mathematica]]

Modern computer algebra systems, as well as many scientific and graphing calculators, allow for "pretty-printing", that is, entry of equations such that fractions, surds and integrals, etc. are displayed in the way they would normally be written. Such calculators are generally similar in appearance to those using infix notation, but feature a full dot-matrix display and templates for entering expressions, which are navigated using arrow keys on the calculator. The templates contain spaces for values or expressions to be entered, and empty values would typically result in a syntax error, making it more cumbersome to navigate than standard infix notation; standard infix notation is often an option on such calculators as well.

Casio used to call this feature Natural Display or Natural textbook display, but now uses Natural-VPAM. Sharp calls this WriteView on its scientific calculators and simply Equation Editor on its graphing calculators. HP calls this its Textbook display setting, which can be used in both RPN and Algebraic mode and in both the Stack and in the Equation Writer application. Mathematica calls this Semantic-Faithful Typesetting. Mathcad calls this standard math notation. Maple has a Math Equation Editor, but does not have a special name for this input method. Texas Instruments calls it MathPrint, incorporating it in its high-end calculators, such as the TI-Nspire series, and in 2011 added the feature to its TI-84 series with the 2.55 OS update.

{| class="wikitable" border="1"

|+ Examples

! Formula

! Keystrokes

! Keystroke Count

| <math>1 + 2 \times 3</math>

| 6

| <math>\sin 30 \times \cos 30</math>

| 9

| <math>5-3</math>

| 4

| <math>15+10+10+10</math>

| 12

For the second example, two options are given, depending on whether the calculators will automatically insert needed parentheses or not. Machines equipped with an alphanumeric display will display <code>SIN(30)×COS(30)</code> before is pressed.

References

</references>

Calculator input methods

Immediate execution

Ten key notation

Mathematical display

See also

References

Further reading