Multiples are easy to find, doubling will give you one, as will simply adding.

A few multiples for 14 are 28, 42, and 56.

Likewise, 24 has some obvious multiples: 48, 72, 96.

Although you could simply find all the multiples of all numbers involved and find the smallest, traditionally this is done by:

1. Reducing all numbers to primes

2. Factoring out common primes

3. Multiplying the smallest collection of primes which includes everything.

By way of example: If you had 10, 14, and 21.

10 is 2 x 5

14 is 2 x 7

21 is 3 x 7

In that list, we have 2, 3, 5, and 7.

So, we'd simply need to multiply each.

2 x 3 x 5 x 7 = 210.

So 210 would be the lowest common multiple in this example.

Sometimes, instead, you have values that have multiple prime factors.

Example: If you had 20, 28, and 21

20 is 2 x 2 x 5

28 is 2 x 2 x 7

21 is 3 x 7

In this list we have 2, 3, 5, and 7 again.

However, 20 needs two 2's.

So our list is: 2, 2, 3, 5, 7.

And we'd again, simply multiply.

2 x 2 x 3 x 5 x 7 = 420.

So 420 would be the lowest common multiple in this example.

In the question above, we have 14, 24 and 36.

14 = 2 x 7

24 = 2 x 2 x 2 x 3

36 = 2 x 2 x 3 x 3

so our list is 2, 2, 2, 3, 3, 7

And 2 x 2 x 2 x 3 x 3 x 7 = 504

Thus, 504 is the LCM for those three numbers.

A few multiples for 14 are 28, 42, and 56.

Likewise, 24 has some obvious multiples: 48, 72, 96.

Although you could simply find all the multiples of all numbers involved and find the smallest, traditionally this is done by:

1. Reducing all numbers to primes

2. Factoring out common primes

3. Multiplying the smallest collection of primes which includes everything.

By way of example: If you had 10, 14, and 21.

10 is 2 x 5

14 is 2 x 7

21 is 3 x 7

In that list, we have 2, 3, 5, and 7.

So, we'd simply need to multiply each.

2 x 3 x 5 x 7 = 210.

So 210 would be the lowest common multiple in this example.

Sometimes, instead, you have values that have multiple prime factors.

Example: If you had 20, 28, and 21

20 is 2 x 2 x 5

28 is 2 x 2 x 7

21 is 3 x 7

In this list we have 2, 3, 5, and 7 again.

However, 20 needs two 2's.

So our list is: 2, 2, 3, 5, 7.

And we'd again, simply multiply.

2 x 2 x 3 x 5 x 7 = 420.

So 420 would be the lowest common multiple in this example.

In the question above, we have 14, 24 and 36.

14 = 2 x 7

24 = 2 x 2 x 2 x 3

36 = 2 x 2 x 3 x 3

so our list is 2, 2, 2, 3, 3, 7

And 2 x 2 x 2 x 3 x 3 x 7 = 504

Thus, 504 is the LCM for those three numbers.