Least Common Multiple (LCM) of 21 and 13
The least common multiple (LCM) of 21 and 13 is 273.
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 13?
First, calculate the GCD of 21 and 13 using the Euclidean algorithm. Then use the formula above to find the LCM.
Step-by-Step GCD Calculation
| Step | Calculation |
|---|---|
| 1 | 21 ÷ 13 = 1 remainder 8 |
| 2 | 13 ÷ 8 = 1 remainder 5 |
| 3 | 8 ÷ 5 = 1 remainder 3 |
| 4 | 5 ÷ 3 = 1 remainder 2 |
| 5 | 3 ÷ 2 = 1 remainder 1 |
| 6 | 2 ÷ 1 = 2 remainder 0 |
Examples of LCM Calculations
| Numbers | LCM |
|---|---|
| 38 and 82 | 1558 |
| 163 and 191 | 31133 |
| 183 and 185 | 33855 |
| 166 and 94 | 7802 |
| 110 and 89 | 9790 |