What does LCM mean in mathematics?

The least common multiple or LCM of two numbers 33 and 21 is defined as the smallest positive integer which is divisible by both of them. It is represented by LCM(33, 21).

Properties of LCM

  • The LCM of two or more prime numbers is exactly equal to their product.
  • LCM is associative which means LCM(33, 21) = LCM(21, 33).
  • LCM is commutative which means LCM(a, b, c) = LCM(LCM(a, b), c) = LCM(a, LCM(b, c)).
  • LCM is distributive, which means LCM(ab, bc, ad) = d * LCM(x, y, z).
  • The LCM of two given numbers is always greater than the given numbers numbers. Eg- LCM of 33 and 21 is 231, where 231 is greater than 33 and 21.

Steps to find lcm of 33 and 21 by Listing Method

Example: Find lcm of 33 and 21 by Listing Method

  • Multiples of 33: 33, 66, 99, 132, 165, 198, 231, 264, 297, 330, 363, 396, 429, 462, 495, 528, 561, 594, 627, 660, 693
  • Multiples of 21: 21, 42, 63, 84, 105, 126, 147, 168, 189, 210, 231, 252, 273, 294, 315, 336, 357, 378, 399, 420, 441, 462, 483, 504, 525, 546, 567, 588, 609, 630, 651, 672, 693

Hence, LCM of 33 and 21 is 231.

Steps to find LCM of 33 and 21 by Common Division Method

Example: Find lcm of 33 and 21 by Common Division Method

3 33 21
7 11 7
11 11 1
1 1

Hence, LCM of 33 and 21 is 3 x 7 x 11 = 231.

Steps to find lcm of 33 and 21 by Formula

Example: Find lcm of 33 and 21 by Formula

  • GCF of 33 and 21 = 3
  • LCM of 33 and 21 = (33 x 21) / 3
  • => 693 / 3

Hence, LCM of 33 and 21 is 231.

Examples

Franky and Joy are running on a circular track. They start at the same time. They take 33 and 21 minutes respectively to go round once. Find at what time they will run together?

Franky and Joy are running on a circular track. They take 33 and 21 minutes respectively to go round once. We need to find out at what time (minimum) they will run together again. For this we need to find the LCM of 33 and 21.
So, LCM of 33 and 21 is 231.

A shopkeeper sells candies in packet of 33 and chocolates in packet of 21. What is the least number of candies and chocolates Annie should buy so that there will be one candy for each chocolate?

The least number of candies and chocolates Annie should buy so that there will be one candy for each chocolate we need to find the lcm of 33 and 21.
So, LCM of 33 and 21 is 231.

Boxes that are 33 inches tall are being pilled next to boxes that are 21 inches tall. What is the least height in feet at which the two piles will be the same height?

To find the least height in feet at which the two piles will be at same height we will find LCM of 33 and 21.
So, LCM of 33 and 21 is 231.

Sammy's company prints 33 textbooks at a time. Daniel's company prints textbooks in sets of 21 at a time. According to a survey done by a committee, both companies printed the same number of textbooks last year. Find the least number of books that each company would have printed.

To find the least number of textbooks that each company could have printed we need to find the LCM of 33 and 21.
So, LCM of 33 and 21 is 231.

What is the relation between LCM and GCF( Greatest Common Factor)?

Greatest common factors or gcf of 33 and 21 is GCF(33, 21) * LCM(33, 21) = (33 x 21) / GCF(33, 21) = 231.

Find the least number which is exactly divisible by 33 and 21.

Least number which is exactly divisible by 33 and 21 is 231.

Find the LCM of 33 and 21 using GCF method.

Greatest common factor or gcf of 33 and 21 is GCF(33, 21) x LCM(33, 21) = (33 x 21) / GCF(33, 21) = 231.