What is LCM of two numbers?

In mathematics, least common multiple which is commonly known as LCM is defined as the smallest non-zero number which is divisible by both given numbers 6 and 81.

Properties of LCM

  • LCM follows associative property, that means LCM(6, 81) = LCM(81, 6).
  • LCM follows commutative property, which means LCM(a, b, c) = LCM(LCM(a, b), c) = LCM(a, LCM(b, c)).
  • LCM follows distributive property, which means LCM(ab, bc, ad) = d * LCM(x, y, z).
  • The LCM of two given numbers is never less than any of those numbers. Eg- LCM of 6 and 81 is 162, where 6 and 81 are less than 162.
  • The LCM of two or more prime numbers is their product.

Steps to find lcm of 6 and 81 by Listing Method

Example: Find lcm of 6 and 81 by Listing Method

  • Multiples of 6: 6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78, 84, 90, 96, 102, 108, 114, 120, 126, 132, 138, 144, 150, 156, 162, 168, 174, 180, 186, 192, 198, 204, 210, 216, 222, 228, 234, 240, 246, 252, 258, 264, 270, 276, 282, 288, 294, 300, 306, 312, 318, 324, 330, 336, 342, 348, 354, 360, 366, 372, 378, 384, 390, 396, 402, 408, 414, 420, 426, 432, 438, 444, 450, 456, 462, 468, 474, 480, 486
  • Multiples of 81: 81, 162, 243, 324, 405, 486

Hence, LCM of 6 and 81 is 162.

Steps to find LCM of 6 and 81 by Common Division Method

Example: Find lcm of 6 and 81 by Common Division Method

2 6 81
3 3 81
3 1 27
3 1 9
3 1 3
1 1

Hence, LCM of 6 and 81 is 2 x 3 x 3 x 3 x 3 = 162.

Steps to find lcm of 6 and 81 by Formula

Example: Find lcm of 6 and 81 by Formula

  • GCF of 6 and 81 = 3
  • LCM of 6 and 81 = (6 x 81) / 3
  • => 486 / 3

Hence, LCM of 6 and 81 is 162.

Examples

Franky and Joy are running on a circular track. They start at the same time. They take 6 and 81 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 6 and 81 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 6 and 81.
So, LCM of 6 and 81 is 162.

A shopkeeper sells candies in packet of 6 and chocolates in packet of 81. 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 6 and 81.
So, LCM of 6 and 81 is 162.

Both the cricket team and the rugby team had games, today. The cricket team plays every 6 days and the basketball team plays every 81 days. When will both teams have games on the same day again?

Given that the cricket team plays every 6 days and the basketball team plays every 81 days, so for finding the next time when both teams will play again we need to find the LCM of 6 and 81.
So, LCM of 6 and 81 is 162.

Freddy saves 6 dollars every day while Nikki saves 81 dollars every day. What is the least number of days it will take each person to save the same amount of money?

To find the least number of days that would be taken to be able to save the same amount of dollars we need to find the LCM of 6 and 81.
So, LCM of 6 and 81 is 162.

Boxes that are 6 inches tall are being pilled next to boxes that are 81 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 6 and 81.
So, LCM of 6 and 81 is 162.

Sammy's company prints 6 textbooks at a time. Daniel's company prints textbooks in sets of 81 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 6 and 81.
So, LCM of 6 and 81 is 162.

Ariel exercises every 6 days and Rubel every 81 days. They both excercised today. How many days will it be until they excercise together again?

The problem can be solved using LCM, because we are trying to figure out the least time until they excercise together again.
So, LCM of 6 and 81 is 162.