The traditional method is to list the multiples of each number and pick the smallest multiple they have in common. This can be very tasking for large numbers. The traditional solution is shown below:
[Method 1]
Steps:
1. List the multiples of each number:
28 - 28, 56, 84, 112, 140...
42 - 42, 84, 126, 168, 210...
2. Pick the smallest multiple they have in common which in this case is 84. If there are no common multiples, continue listing multiples until a common multiple is produced.
[Method 2 - Prime factorization Method]
Steps:
1. Find the prime factorization of each number.
28 - 2*2*7
42 - 2*3*7
2. Circle the prime factors they have in common one pair at a time.
One pair of twos and one pair of sevens.
The other 2 and 3 remain uncircled.
3. Multiply one number from each of the pairs by each of the uncircled prime factors remaining to get the LCM (least common multiple).
2*7*2*3 = 84
Least Common Multiple is 84
420
The least common multiple of the numbers 2,842 and 56 is 11,368.The least common multiple of the numbers 28, 42 and 56 is 168.
The least common multiple of 42 and 25 is 1050.
The least common multiple of the numbers 28, 42 and 56 is 168.
The Least Common Multiple (LCM) for 28 42 is 84.
The least common multiple of the numbers 28, 35 and 42 is 420.
The least common multiple of 28, 42, and 108 is 756.
The Least Common Multiple (LCM) for 42 28 is 84.
Least Common Multiple is 84
84
84
The Least Common Multiple (LCM) of (28,42,24) is 168
The least common multiple of 42 , 28 , 108 = 756
LCM(21, 28, 42) = 84.
The LCM is: 168
420