Enter an equation or problem
Camera input is not recognized!

Solution - Least common multiple (LCM) by prime factorization

1,296
1,296

Step-by-step explanation

1. Find the prime factors of 72

Tree view of the prime factors of 72: 2, 2, 2, 3 and 3

The prime factors of 72 are 2, 2, 2, 3 and 3.

2. Find the prime factors of 108

Tree view of the prime factors of 108: 2, 2, 3, 3 and 3

The prime factors of 108 are 2, 2, 3, 3 and 3.

3. Find the prime factors of 144

Tree view of the prime factors of 144: 2, 2, 2, 2, 3 and 3

The prime factors of 144 are 2, 2, 2, 2, 3 and 3.

4. Find the prime factors of 162

Tree view of the prime factors of 162: 2, 3, 3, 3 and 3

The prime factors of 162 are 2, 3, 3, 3 and 3.

5. Build a prime factors table

Determine the maximum number of times each prime factor (2, 3) occurs in the factorization of the given numbers:

Prime factorNumber72 108 144 162 Max. occurrence
232414
323244

The prime factors 2 and 3 occur more than once.

6. Calculate the LCM

The least common multiple is the product of all factors in the greatest number of their occurrence.

LCM = 22223333

LCM = 2434

LCM = 1,296

The least common multiple of 72, 108, 144 and 162 is 1,296.

Why learn this

The least common multiple (LCM), sometimes called the lowest common multiple or least common divisor, is helpful for understanding the relationships between numbers. For example, if it takes Earth 365 days to orbit the sun and it takes Venus 225 days to orbit the sun and both are in perfect alignment at the time this scenario is given, how long will it take for Earth and Venus to align again? We can use LCM to determine that the answer would be 16,425 days.

LCM is also a very important part of many mathematical concepts that also have real-world applications. For example, we use LCMs when adding and subtracting fractions, which we use quite frequently.