Least Common Multiple (LCM) of 40 and 21
The least common multiple (LCM) of 40 and 21 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 40 and 21?
First, calculate the GCD of 40 and 21 using the Euclidean algorithm. Then use the formula above to find the LCM.
Step-by-Step GCD Calculation
| Step | Calculation |
|---|---|
| 1 | 40 ÷ 21 = 1 remainder 19 |
| 2 | 21 ÷ 19 = 1 remainder 2 |
| 3 | 19 ÷ 2 = 9 remainder 1 |
| 4 | 2 ÷ 1 = 2 remainder 0 |
Examples of LCM Calculations
| Numbers | LCM |
|---|---|
| 192 and 28 | 1344 |
| 121 and 163 | 19723 |
| 60 and 132 | 660 |
| 165 and 72 | 3960 |
| 139 and 69 | 9591 |