Diseases, Conditions, Syndromes

COPD set to reach about 600 million cases worldwide by 2050

The prevalence of chronic obstructive pulmonary disease (COPD) is projected to continue increasing through 2050, approaching 600 million patients with COPD globally by 2050, according to a study published online Dec. 7 in ...


South Africa AIDS epidemic eases: survey

South Africa has recorded its first significant fall in the number of people suffering from HIV but remains in the grip of a sexually transmitted epidemic, according to a survey released on Monday.


Babies are losing their lives to a preventable illness

Cases of syphilis have skyrocketed in L.A. County and across the country, with devastating results. Left untreated in adults, it can damage organs and infiltrate the brain, possibly leading to dementia and blindness. Men ...

Medical economics

Many Americans facing financial ruin as costs soar for elder care

Margaret Newcomb, 69, a retired French teacher, is desperately trying to protect her retirement savings by caring for her 82-year-old husband, who has severe dementia, at home in Seattle. She used to fear his disease-induced ...

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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