LCM of 4 and 5
The least common multiple of 4 and 5 is 20 — the smallest positive number into which both 4 and 5 divide evenly. This page lists the first twelve common multiples of the pair, which are exactly the multiples of 20.
4 and 5 share no common factor greater than 1, so their multiples first coincide only after a full 4 × 5 sweep: the LCM is the plain product 20. The number lines advance out of step — 4 every 4, 5 every 5 — and nothing shortens the wait. Because GCF(4, 5) = 1, the identity LCM × GCF = a × b reads 20 × 1 = 20, and the common multiples march outward at 20, 40, 60, and beyond.
| # | Common multiple |
|---|---|
| 1 | 20 |
| 2 | 40 |
| 3 | 60 |
| 4 | 80 |
| 5 | 100 |
| 6 | 120 |
| 7 | 140 |
| 8 | 160 |
| 9 | 180 |
| 10 | 200 |
| 11 | 220 |
| 12 | 240 |
Frequently asked questions
What is the LCM of 4 and 5?
The least common multiple of 4 and 5 is 20. The multiples of 4 begin 4, 8, 12, 16, … and the multiples of 5 begin 5, 10, 15, …, and 20 is the first value both lists share. Formula check: (4 × 5) ÷ GCF(4, 5) = 20 ÷ 1 = 20.
How do you find the LCM of 4 and 5?
Compare prime factorizations: 4 = 2² and 5 = 5. No prime is shared, so every prime enters at full power and the product is the LCM: 20. The shortcut through the GCF lands on the same value: (4 × 5) ÷ 1 = 20.
What is the GCF of 4 and 5?
1. The factorizations 2² and 5 share no prime, so 1 is the greatest common factor. The companion identity holds anyway: GCF × LCM = 4 × 5, or 1 × 20 = 20.
What are the common multiples of 4 and 5?
Exactly the multiples of the LCM: 20, 40, 60, 80, 100, 120, and onward without end. The table above lists the first twelve; every later one is another 20 steps out. These are the numbers into which both 4 and 5 divide evenly — which is why the LCM itself is the natural common denominator in fraction work.