Greatest Common Divisor (GCD) of 120 and 171
The greatest common divisor (GCD) of 120 and 171 is 3.
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 120 and 171?
We use the Euclidean algorithm, which involves the following steps:
- Divide the larger number by the smaller number.
- Replace the larger number with the smaller number and the smaller number with the remainder from the division.
- Repeat this process until the remainder is zero.
- The non-zero remainder just before zero is the GCD.
Step-by-Step Euclidean Algorithm
| Step | Calculation |
|---|---|
| 1 | 120 ÷ 171 = 0 remainder 120 |
| 2 | 171 ÷ 120 = 1 remainder 51 |
| 3 | 120 ÷ 51 = 2 remainder 18 |
| 4 | 51 ÷ 18 = 2 remainder 15 |
| 5 | 18 ÷ 15 = 1 remainder 3 |
| 6 | 15 ÷ 3 = 5 remainder 0 |
Examples of GCD Calculations
| Numbers | GCD |
|---|---|
| 110 and 145 | 5 |
| 51 and 198 | 3 |
| 108 and 193 | 1 |
| 125 and 129 | 1 |
| 106 and 125 | 1 |