Greatest Common Divisor (GCD) of 120 and 155
The greatest common divisor (GCD) of 120 and 155 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 120 and 155?
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 ÷ 155 = 0 remainder 120 |
| 2 | 155 ÷ 120 = 1 remainder 35 |
| 3 | 120 ÷ 35 = 3 remainder 15 |
| 4 | 35 ÷ 15 = 2 remainder 5 |
| 5 | 15 ÷ 5 = 3 remainder 0 |
Examples of GCD Calculations
| Numbers | GCD |
|---|---|
| 100 and 196 | 4 |
| 69 and 197 | 1 |
| 51 and 133 | 1 |
| 174 and 161 | 1 |
| 138 and 62 | 2 |