Calculate the Least Common Multiple or LCM of 56, 84, 105 and 128
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The instructions to find the LCM of 56, 84, 105 and 128 are the next:
1. Decompose all numbers into prime factors
56 | 2 |
28 | 2 |
14 | 2 |
7 | 7 |
1 |
84 | 2 |
42 | 2 |
21 | 3 |
7 | 7 |
1 |
105 | 3 |
35 | 5 |
7 | 7 |
1 |
128 | 2 |
64 | 2 |
32 | 2 |
16 | 2 |
8 | 2 |
4 | 2 |
2 | 2 |
1 |
2. Write all numbers as the product of its prime factors
Prime factors of 56 | = | 23 . 7 |
Prime factors of 84 | = | 22 . 3 . 7 |
Prime factors of 105 | = | 3 . 5 . 7 |
Prime factors of 128 | = | 27 |
3. Choose the common and uncommon prime factors with the greatest exponent
Common prime factors: None
Common prime factors with the greatest exponent: None
Uncommon prime factors: 2 , 7 , 3 , 5
Uncommon prime factors with the greatest exponent: 27, 71, 31, 51
4. Calculate the Least Common Multiple or LCM
Remember, to find the LCM of several numbers you must multiply the common and uncommon prime factors with the greatest exponent of those numbers.
LCM = 27. 71. 31. 51 = 13440
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