Least Common Multiple (LCM) of 21 and 57
The least common multiple (LCM) of 21 and 57 is 399.
What is the Least Common Multiple (LCM)?
The LCM of two integers is the smallest positive integer that is divisible by both numbers. It is often used to find common denominators and solve problems involving periodic events.
Formula for LCM
The LCM of two numbers can be calculated using their GCD:
LCM(a, b) = |a × b| ÷ GCD(a, b)
How to Calculate the LCM of 21 and 57?
First, calculate the GCD of 21 and 57 using the Euclidean algorithm. Then use the formula above to find the LCM.
Step-by-Step GCD Calculation
| Step | Calculation |
|---|---|
| 1 | 21 ÷ 57 = 0 remainder 21 |
| 2 | 57 ÷ 21 = 2 remainder 15 |
| 3 | 21 ÷ 15 = 1 remainder 6 |
| 4 | 15 ÷ 6 = 2 remainder 3 |
| 5 | 6 ÷ 3 = 2 remainder 0 |
Examples of LCM Calculations
| Numbers | LCM |
|---|---|
| 146 and 130 | 9490 |
| 167 and 144 | 24048 |
| 132 and 183 | 8052 |
| 162 and 14 | 1134 |
| 81 and 67 | 5427 |