## News tagged with number

### Parental absence affects brain development in children

Researchers in China have found that children who have been left without direct parental care for extended periods of time show larger gray matter volumes in the brain, according to a study being presented today at the annual ...

Nov 30, 2015
50 0

### Always forget a face? So does Brad Pitt – don't just blame your memory

Most of us occasionally fail to recognise people we know. This often happens when we meet someone we know in an unusual context, such as bumping into a work colleague in a supermarket. Nevertheless, the ability to recognise ...

22 hours ago
3 0

### Doubling numbers on HIV drugs could 'break' epidemic: UN (Update)

The UN on Tuesday urged countries to "break the AIDS epidemic" by doubling the number of people receiving HIV treatment within the next five years.

Nov 24, 2015
0 0

### Heart disease doesn't take a holiday

(HealthDay)—People with heart disease should take a number of precautions if they travel over the Thanksgiving holiday, an expert suggests.

Nov 25, 2015
0 0

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## Number

A number is a mathematical object used to count and measure. In mathematics, the definition of number has been extended over the years to include such numbers as zero, negative numbers, rational numbers, irrational numbers, and complex numbers.

Mathematical operations are certain procedures that take one or more numbers as input and produce a number as output. Unary operations take a single input number and produce a single output number. For example, the successor operation adds one to an integer, thus the successor of 4 is 5. Binary operations take two input numbers and produce a single output number. Examples of binary operations include addition, subtraction, multiplication, division, and exponentiation. The study of numerical operations is called arithmetic.

A notational symbol that represents a number is called a numeral. In addition to their use in counting and measuring, numerals are often used for labels (telephone numbers), for ordering (serial numbers), and for codes (e.g., ISBNs).

In common use, the word number can mean the abstract object, the symbol, or the word for the number.

This text uses material from Wikipedia, licensed under CC BY-SA