The working out of a value by fixed steps. Calculation is reasoning done so anyone can repeat it.

The digits after the point. Decimals state precision and say nothing about accuracy.

A closed set of permitted values, named one by one. Its meaning is as much in what it excludes as in what it lists.

A compound fragment meaning a name index. Not an English word; flagged for the mis-cut band.

A count or a measure, held as a value. A number carries no meaning until someone says what it counted.

Short form of sequence — things in a fixed order where the order carries meaning. A named abbreviation.