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Greatest Common Divisor (GCD) of 155 and 120

The greatest common divisor (GCD) of 155 and 120 is 5.

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 155 and 120?

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
1 155 ÷ 120 = 1 remainder 35
2 120 ÷ 35 = 3 remainder 15
3 35 ÷ 15 = 2 remainder 5
4 15 ÷ 5 = 3 remainder 0

Examples of GCD Calculations

NumbersGCD
107 and 191
104 and 248
137 and 137137
189 and 987
180 and 191

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