Least Common Multiple (LCM) of 21 and 51
The least common multiple (LCM) of 21 and 51 is 357.
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 51?
First, calculate the GCD of 21 and 51 using the Euclidean algorithm. Then use the formula above to find the LCM.
Step-by-Step GCD Calculation
| Step | Calculation |
|---|---|
| 1 | 21 ÷ 51 = 0 remainder 21 |
| 2 | 51 ÷ 21 = 2 remainder 9 |
| 3 | 21 ÷ 9 = 2 remainder 3 |
| 4 | 9 ÷ 3 = 3 remainder 0 |
Examples of LCM Calculations
| Numbers | LCM |
|---|---|
| 199 and 135 | 26865 |
| 74 and 18 | 666 |
| 144 and 151 | 21744 |
| 30 and 109 | 3270 |
| 76 and 25 | 1900 |