Question

lcm of 21, 33, 57

Answer 1

Break each number down into factors. 21=3*7; 33=3*11; 57=3*19. Now write down the factors with no duplication: 3, 7, 11, 19. Multiply these factors together: 4389=3*7*11*19, that's the LCM. Look at 4389 broken down into its factors and you can see 3 and 7 (21), 3 and 11 (33), and 3 and 19 (57). It's all a matter of picking from a set of factors those you need to make up each individual number. All you have to do is find out what the set contains by analysing the numbers, breaking them down into their factors.

Answer 2

The Least Common Multiple (LCM) is also referred to as the Lowest Common Multiple (LCM) and Least Common Denominator (LCD). For 2 integers a and b, denoted LCM(a,b), it is the smallest integer that is evenly divisible by both a and b. For example, LCM(2,3) = 6 and LCM(6,10) = 30. For the least common multiple of more than 2 numbers, say a, b, c and d, it is the smallest integer that is evenly divisible by all numbers and can be calculated such that LCM(a,b,c,d) = LCM(LCM(LCM(a,b),c),d)

For the values: 57, 33, 21
The LCM is: 4389

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