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Greatest Common Divisor (GCD) of 128 and 38

The greatest common divisor (GCD) of 128 and 38 is 2.

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 128 and 38?

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
1 128 ÷ 38 = 3 remainder 14
2 38 ÷ 14 = 2 remainder 10
3 14 ÷ 10 = 1 remainder 4
4 10 ÷ 4 = 2 remainder 2
5 4 ÷ 2 = 2 remainder 0

Examples of GCD Calculations

NumbersGCD
91 and 1221
136 and 1448
80 and 1591
66 and 102
170 and 242

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