Greatest Common Divisor (GCD) of 81 and 13
The greatest common divisor (GCD) of 81 and 13 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 81 and 13?
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 | 81 ÷ 13 = 6 remainder 3 |
| 2 | 13 ÷ 3 = 4 remainder 1 |
| 3 | 3 ÷ 1 = 3 remainder 0 |
Examples of GCD Calculations
| Numbers | GCD |
|---|---|
| 23 and 15 | 1 |
| 109 and 62 | 1 |
| 145 and 22 | 1 |
| 194 and 199 | 1 |
| 82 and 189 | 1 |