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Greatest Common Divisor (GCD) of 84 and 42

The greatest common divisor (GCD) of 84 and 42 is 42.

What is the Greatest Common Divisor (GCD)?

The GCD of two integers is the largest positive integer that divides both numbers without leaving a remainder. It is useful in simplifying fractions, finding common factors, and in number theory.

How to Calculate the GCD of 84 and 42?

We use the Euclidean algorithm, which involves the following steps:

  1. Divide the larger number by the smaller number.
  2. Replace the larger number with the smaller number and the smaller number with the remainder from the division.
  3. Repeat this process until the remainder is zero.
  4. The non-zero remainder just before zero is the GCD.

Step-by-Step Euclidean Algorithm

StepCalculation
1 84 ÷ 42 = 2 remainder 0

Examples of GCD Calculations

NumbersGCD
111 and 1361
19 and 1841
43 and 17243
14 and 651
133 and 511

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