Greatest Common Divisor (GCD) of 31 and 78
The greatest common divisor (GCD) of 31 and 78 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 31 and 78?
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 | 31 ÷ 78 = 0 remainder 31 |
| 2 | 78 ÷ 31 = 2 remainder 16 |
| 3 | 31 ÷ 16 = 1 remainder 15 |
| 4 | 16 ÷ 15 = 1 remainder 1 |
| 5 | 15 ÷ 1 = 15 remainder 0 |
Examples of GCD Calculations
| Numbers | GCD |
|---|---|
| 38 and 74 | 2 |
| 161 and 200 | 1 |
| 72 and 182 | 2 |
| 111 and 132 | 3 |
| 100 and 169 | 1 |