Definition of LCM

LCM stands for least common multiple. In mathematics, LCM of two numbers 210 and 28, is defined as the smallest positive integer that is divisible by both. It is written as LCM(210, 28).

Properties of LCM

  • LCM follows associative property, that means LCM(210, 28) = LCM(28, 210).
  • 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 210 and 28 is 420, where 210 and 28 are less than 420.
  • The LCM of two or more prime numbers is their product.

Steps to find lcm of 210 and 28 by Listing Method

Example: Find lcm of 210 and 28 by Listing Method

  • Multiples of 210: 210, 420, 630, 840, 1050, 1260, 1470, 1680, 1890, 2100, 2310, 2520, 2730, 2940, 3150, 3360, 3570, 3780, 3990, 4200, 4410, 4620, 4830, 5040, 5250, 5460, 5670, 5880
  • Multiples of 28: 28, 56, 84, 112, 140, 168, 196, 224, 252, 280, 308, 336, 364, 392, 420, 448, 476, 504, 532, 560, 588, 616, 644, 672, 700, 728, 756, 784, 812, 840, 868, 896, 924, 952, 980, 1008, 1036, 1064, 1092, 1120, 1148, 1176, 1204, 1232, 1260, 1288, 1316, 1344, 1372, 1400, 1428, 1456, 1484, 1512, 1540, 1568, 1596, 1624, 1652, 1680, 1708, 1736, 1764, 1792, 1820, 1848, 1876, 1904, 1932, 1960, 1988, 2016, 2044, 2072, 2100, 2128, 2156, 2184, 2212, 2240, 2268, 2296, 2324, 2352, 2380, 2408, 2436, 2464, 2492, 2520, 2548, 2576, 2604, 2632, 2660, 2688, 2716, 2744, 2772, 2800, 2828, 2856, 2884, 2912, 2940, 2968, 2996, 3024, 3052, 3080, 3108, 3136, 3164, 3192, 3220, 3248, 3276, 3304, 3332, 3360, 3388, 3416, 3444, 3472, 3500, 3528, 3556, 3584, 3612, 3640, 3668, 3696, 3724, 3752, 3780, 3808, 3836, 3864, 3892, 3920, 3948, 3976, 4004, 4032, 4060, 4088, 4116, 4144, 4172, 4200, 4228, 4256, 4284, 4312, 4340, 4368, 4396, 4424, 4452, 4480, 4508, 4536, 4564, 4592, 4620, 4648, 4676, 4704, 4732, 4760, 4788, 4816, 4844, 4872, 4900, 4928, 4956, 4984, 5012, 5040, 5068, 5096, 5124, 5152, 5180, 5208, 5236, 5264, 5292, 5320, 5348, 5376, 5404, 5432, 5460, 5488, 5516, 5544, 5572, 5600, 5628, 5656, 5684, 5712, 5740, 5768, 5796, 5824, 5852, 5880

Hence, LCM of 210 and 28 is 420.

Steps to find LCM of 210 and 28 by Common Division Method

Example: Find lcm of 210 and 28 by Common Division Method

2 210 28
2 105 14
3 105 7
5 35 7
7 7 7
1 1

Hence, LCM of 210 and 28 is 2 x 2 x 3 x 5 x 7 = 420.

Steps to find lcm of 210 and 28 by Formula

Example: Find lcm of 210 and 28 by Formula

  • GCF of 210 and 28 = 14
  • LCM of 210 and 28 = (210 x 28) / 14
  • => 5880 / 14

Hence, LCM of 210 and 28 is 420.

Examples

A shopkeeper sells candies in packet of 210 and chocolates in packet of 28. 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 210 and 28.
So, LCM of 210 and 28 is 420.

Both the cricket team and the rugby team had games, today. The cricket team plays every 210 days and the basketball team plays every 28 days. When will both teams have games on the same day again?

Given that the cricket team plays every 210 days and the basketball team plays every 28 days, so for finding the next time when both teams will play again we need to find the LCM of 210 and 28.
So, LCM of 210 and 28 is 420.

Steve spends 210 dollars every day while George spends 28 dollars every day. What is the least number of days it will take each person to spend the same amount of money?

To find the least number of days that would be taken to be able to spend the same amount of dollars we need to find the LCM of 210 and 28.
So, LCM of 210 and 28 is 420.

Sammy's company prints 210 textbooks at a time. Daniel's company prints textbooks in sets of 28 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 210 and 28.
So, LCM of 210 and 28 is 420.

Ariel exercises every 210 days and Rubel every 28 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 210 and 28 is 420.

Find the least common multiple of 210 and 28.

Least common multiple of 210 and 28 is 420.

Find the least number which is exactly divisible by 210 and 28.

Least number which is exactly divisible by 210 and 28 is 420.