Least Common Multiple (LCM) of 21 and 120
The least common multiple (LCM) of 21 and 120 is 840.
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 120?
First, calculate the GCD of 21 and 120 using the Euclidean algorithm. Then use the formula above to find the LCM.
Step-by-Step GCD Calculation
| Step | Calculation |
|---|---|
| 1 | 21 ÷ 120 = 0 remainder 21 |
| 2 | 120 ÷ 21 = 5 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 |
|---|---|
| 154 and 75 | 11550 |
| 21 and 197 | 4137 |
| 25 and 121 | 3025 |
| 25 and 49 | 1225 |
| 168 and 118 | 9912 |