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Clock arithmetic

Definition

Clock arithmetic, also known as modular arithmetic, is a system of arithmetic for integers where numbers wrap around after reaching a certain value, the modulus. It is often visualized using the numbers on a clock face where, for example, 13 o'clock is equivalent to 1 o'clock in modulo 12.

5 Must Know Facts For Your Next Test

  1. In clock arithmetic with modulus n, any integer can be reduced to a number between 0 and n-1.
  2. Addition and multiplication operations in clock arithmetic are performed by adding or multiplying numbers and then taking the remainder when divided by the modulus.
  3. Clock arithmetic is fundamental in number theory and has applications in cryptography and computer science.
  4. If two numbers have the same remainder when divided by the modulus, they are considered congruent modulo that modulus.
  5. The notation 'a โ‰ก b (mod n)' denotes that a and b leave the same remainder when divided by n.

Review Questions

  • What is 17 mod 5?
  • Explain how you would calculate (7 + 9) mod 12.
  • Why are numbers like -3 relevant in modular arithmetic?

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Related terms

Modulus: The fixed number at which values reset or wrap around in modular arithmetic.

Congruence: A relationship indicating that two numbers have the same remainder when divided by a given modulus.

Residue: The remainder left after division of one number by another.



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ยฉ 2024 Fiveable Inc. All rights reserved.

APยฎ and SATยฎ are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.