Least Common Multiple (LCM) of 21 and 105
The least common multiple (LCM) of 21 and 105 is 105.
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 105?
First, calculate the GCD of 21 and 105 using the Euclidean algorithm. Then use the formula above to find the LCM.
Step-by-Step GCD Calculation
| Step | Calculation |
|---|---|
| 1 | 21 ÷ 105 = 0 remainder 21 |
| 2 | 105 ÷ 21 = 5 remainder 0 |
Examples of LCM Calculations
| Numbers | LCM |
|---|---|
| 129 and 87 | 3741 |
| 117 and 80 | 9360 |
| 125 and 150 | 750 |
| 122 and 15 | 1830 |
| 195 and 30 | 390 |