Greatest Common Divisor (GCD) of 128 and 191
The greatest common divisor (GCD) of 128 and 191 is 1.
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 191?
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 | 128 ÷ 191 = 0 remainder 128 |
| 2 | 191 ÷ 128 = 1 remainder 63 |
| 3 | 128 ÷ 63 = 2 remainder 2 |
| 4 | 63 ÷ 2 = 31 remainder 1 |
| 5 | 2 ÷ 1 = 2 remainder 0 |
Examples of GCD Calculations
| Numbers | GCD |
|---|---|
| 145 and 90 | 5 |
| 81 and 21 | 3 |
| 68 and 125 | 1 |
| 195 and 124 | 1 |
| 53 and 26 | 1 |