Diseases, Conditions, Syndromes

WHO: COVID cases and deaths falling nearly everywhere

The number of new coronavirus cases and deaths reported globally fell everywhere last week except the Middle East and Southeast Asia, according to the World Health Organization.

Oncology & Cancer

Number of mesothelioma deaths up among women from 1999 to 2020

From 1999 to 2020, there was an increase in the annual number of mesothelioma deaths among women, although the age-adjusted death rate decreased, according to research published in the May 13 issue of the U.S. Centers for ...

Medical economics

30 million people of all ages uninsured in U.S. in 2021

In 2021, 30.0 million people of all ages were uninsured in the United States, representing a small, but not significant, decrease from 2020, according to early estimates from the National Health Interview Survey, 2021, released ...

Diseases, Conditions, Syndromes

S.Africa Covid cases at highest level in months

South Africa is witnessing a "worrying" spike in coronavirus cases after a relative lull in new infections, official data showed Friday.

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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.

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