LCM for 21 and 40
"Least Common Multiple" Calculator
What's the Least Common Multiple (LCM) of 21 and 40?
Answer
LCM of 21 and 40 is
840
First common multiples: 840; 1,680; 2,520; …
840 is divisible by both: 840 ÷ 21 = 40, 840 ÷ 40 = 21 — and 40 and 21 share no factor but 1, so no smaller number is. As a common denominator: multiply the top and bottom of x/21 by 40 and of y/40 by 21.
21 and 40 are coprime (GCF = 1), so their LCM is simply the product: 21 × 40 = 840.
21 = 3 × 7
40 = 23 × 5
| Prime | 21 | 40 | Highest power |
|---|---|---|---|
| 2 | — | 23 | 23 |
| 3 | 3 | — | 3 |
| 5 | — | 5 | 5 |
| 7 | 7 | — | 7 |
— = power 0: the prime is not a factor of this number; the LCM takes it from the number that has it.
LCM = 23 × 3 × 5 × 7 = 840
More with these numbers
Found an error in the calculation or the information?
Related Calculations
See Also
- Greatest Common Factor - Find the Greatest Common Factor (GCF) of two numbers
- Least Common Multiple of 3 Numbers - Find the Least Common Multiple (LCM) of three numbers
- Greatest Common Factor of 3 Numbers - Find the Greatest Common Factor (GCF) of three numbers
- Multiples of a Number - List the first 10 multiples of any number from 1 to 999
Share This Calculation
Print
<a href="https://calculat.io/en/number/least-common-multiple-lcm-of/21--40">What is the LCM of 21 and 40? - Calculatio</a>Facebook
Twitter
Telegram
WhatsApp
Viber
Email
