9 is the fourth composite number, and the first odd composite number. 9 is also a refactorable number. [2] Casting out nines is a quick way of testing the calculations of sums, differences, products, and quotients of integers in decimal, a method known as long ago as …

"Revolution 9" is a sound collage from the Beatles' 1968 self-titled double album (also known as the "White Album"). The composition, credited to Lennon–McCartney, was created primarily by John Lennon with assistance from Yoko Ono and George Harrison. Lennon said he was trying to paint a picture of a revolution using sound.

Algebraic number: Any number that is the root of a non-zero polynomial with rational coefficients. Transcendental number: Any real or complex number that is not algebraic. Examples include e and π. Trigonometric number: Any number that is the sine or cosine of a rational multiple of π.

90 is the third unitary perfect number (after 6 and 60), since it is the sum of its unitary divisors excluding itself, [22] and because it is equal to the sum of a subset of its divisors, it is also the twenty-first semiperfect number.

911, sometimes written 9-1-1, is an emergency telephone number for Argentina, Canada, the Dominican Republic, Fiji, Jordan, Mexico, Pakistan, Maldives, Palau, Panama, Iraq, the Philippines, Sint Maarten, the United States, [2] and Uruguay, as well as the North American Numbering Plan (NANP), one of eight N11 codes. Like other emergency numbers ...

910 = 2 × 5 × 7 × 13, Mertens function(910) returns 0, Harshad number, happy number, balanced number, [8] number of polynomial symmetric functions of matrix of order 7 under separate row and column permutations [9] 911 = Sophie Germain prime number, also the emergency telephone number in North America

Inside No. 9 is a British black comedy anthology television programme written and created by Steve Pemberton and Reece Shearsmith. It aired on BBC Two from 5 February 2014 to 12 June 2024, running for 9 series and 55 episodes. Each 30-minute episode is a self-contained story with new characters and a new setting, almost all starring Pemberton ...

Stylistic impression of the repeating decimal 0.9999..., representing the digit 9 repeating infinitely. In mathematics, 0.999... (also written as 0. 9, 0.., or 0.(9)) is a repeating decimal that is an alternative way of writing the number 1.

The 9 Broadway–Seventh Avenue Local [1] was a rapid transit service in the A Division of the New York City Subway. Its route emblem, or "bullet", was colored red, [ 1 ] the color used by trains on the Interborough Rapid Transit Company 's (IRT) Broadway–Seventh Avenue Line .

Square number 16 as sum of gnomons. In mathematics, a square number or perfect square is an integer that is the square of an integer; [1] in other words, it is the product of some integer with itself. For example, 9 is a square number, since it equals 3 2 and can be written as 3 × 3.