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Ceiling function

From AoPSWiki

The ceiling function, also known as the "least integer function," gives the least integer greater than or equal to its argument. The ceiling of x is usually denoted by \lceil x \rceil. The action of the function is also described by the phrase "rounding up." On the negative real numbers, this corresponds to the action "dropping everything after the decimal point".

Examples

  • \lceil 3.14 \rceil = 4
  • \lceil 5 \rceil = 5
  • \lceil -3.2\rceil = -3

Relation to the Floor Function

For an integer, the ceiling function is equal to the floor function. For any other number, the ceiling function is the floor function plus one.

See Also

Want to learn how to tackle those tough AMC/AIME/Olympiad algebra problems? Check out Art of Problem Solving's Intermediate Algebra by Richard Rusczyk and Mathew Crawford. Over 1600 problems!
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