Calculators

Modern electronic calculators has a keyboard with keys (buttons) for digits and arithmetical operations.

Some calculators have "double zero" and "tipple zero" keys (00 and 000) that makes large numbers faster to enter.

Most basic calculators assign only one digit or operation to each button. However, in specialized calculators, a button can perform multiple functions.

Calculators have liquid crystal displays. Old calculators used vacuum fluorescent displays.

Fractions such as 1/3 are displayed as decimal approximations, in this case 0.33333333.

Some fractions such as 1/7 (0.14285714285714 to 14 significant figures) can be difficult to recognize in decimal form; to make it easier, many scientific calculators are able to work in vulgar fractions or mixed numbers.

Calculators have the ability to store numbers in memory. Basic calculators store only one number at a time.

Specialized calculators are able to store many numbers represented in variables. The variables can also be used to construct formulae.

Some calculators have the ability to extend memory capacity to store many numbers and formulae; the extended address is referred to as an array index.

Calculators may be powered by batteries, solar cells or electricity, or a combination of these.

Basic calculator keys:

MC Memory Clear
M+ Memory Addition
M- Memory Subtraction
MR Memory Recall
C Clear display (last entered number, whereas CE: Clear everything)
+/-Toggle positive/negative number
/ Division
x Multiplication (may also be asterisk *)
- Subtraction
+ Addition
. Decimal point
= Result