Least Common Multiple (LCM) of 21 and 87
The least common multiple (LCM) of 21 and 87 is 609.
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 87?
First, calculate the GCD of 21 and 87 using the Euclidean algorithm. Then use the formula above to find the LCM.
Step-by-Step GCD Calculation
| Step | Calculation |
|---|---|
| 1 | 21 ÷ 87 = 0 remainder 21 |
| 2 | 87 ÷ 21 = 4 remainder 3 |
| 3 | 21 ÷ 3 = 7 remainder 0 |
Examples of LCM Calculations
| Numbers | LCM |
|---|---|
| 79 and 12 | 948 |
| 71 and 18 | 1278 |
| 116 and 19 | 2204 |
| 189 and 40 | 7560 |
| 173 and 29 | 5017 |