Greatest Common Divisor (GCD) of 81 and 180
The greatest common divisor (GCD) of 81 and 180 is 9.
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 180?
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 ÷ 180 = 0 remainder 81 |
| 2 | 180 ÷ 81 = 2 remainder 18 |
| 3 | 81 ÷ 18 = 4 remainder 9 |
| 4 | 18 ÷ 9 = 2 remainder 0 |
Examples of GCD Calculations
| Numbers | GCD |
|---|---|
| 106 and 128 | 2 |
| 160 and 112 | 16 |
| 172 and 87 | 1 |
| 122 and 172 | 2 |
| 71 and 163 | 1 |